Publications by authors named "Irving L Weissman"

391 Publications

Distinct skeletal stem cell types orchestrate long bone skeletogenesis.

Elife 2021 Jul 19;10. Epub 2021 Jul 19.

Institute for Stem Cell Biology and Regenerative Medicine, Stanford University School of Medicine, Stanford, United States.

Skeletal stem and progenitor cell populations are crucial for bone physiology. Characterization of these cell types remains restricted to heterogenous bulk populations with limited information on whether they are unique or overlap with previously characterized cell types. Here we show, through comprehensive functional and single-cell transcriptomic analyses, that postnatal long bones of mice contain at least two types of bone progenitors with bona fide skeletal stem cell (SSC) characteristics. An early osteochondral SSC (ocSSC) facilitates long bone growth and repair, while a second type, a perivascular SSC (pvSSC), co-emerges with long bone marrow and contributes to shape the hematopoietic stem cell niche and regenerative demand. We establish that pvSSCs, but not ocSSCs, are the origin of bone marrow adipose tissue. Lastly, we also provide insight into residual SSC heterogeneity as well as potential crosstalk between the two spatially distinct cell populations. These findings comprehensively address previously unappreciated shortcomings of SSC research.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.7554/eLife.66063DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8289409PMC
July 2021

Combining CD47 blockade with trastuzumab eliminates HER2-positive breast cancer cells and overcomes trastuzumab tolerance.

Proc Natl Acad Sci U S A 2021 Jul;118(29)

Institute for Stem Cell Biology and Regenerative Medicine, Ludwig Center for Cancer Stem Cell Research, Stanford University, Stanford, CA 94305;

Trastuzumab, a targeted anti-human epidermal-growth-factor receptor-2 (HER2) monoclonal antibody, represents a mainstay in the treatment of HER2-positive (HER2) breast cancer. Although trastuzumab treatment is highly efficacious for early-stage HER2 breast cancer, the majority of advanced-stage HER2 breast cancer patients who initially respond to trastuzumab acquire resistance to treatment and relapse, despite persistence of HER2 gene amplification/overexpression. Here, we sought to leverage HER2 overexpression to engage antibody-dependent cellular phagocytosis (ADCP) through a combination of trastuzumab and anti-CD47 macrophage checkpoint immunotherapy. We have previously shown that blockade of CD47, a surface protein expressed by many malignancies (including HER2 breast cancer), is an effective anticancer therapy. CD47 functions as a "don't eat me" signal through its interaction with signal regulatory protein-α (SIRPα) on macrophages to inhibit phagocytosis. Hu5F9-G4 (magrolimab), a humanized monoclonal antibody against CD47, blocks CD47's "don't eat me" signal, thereby facilitating macrophage-mediated phagocytosis. Preclinical studies have shown that combining Hu5F9-G4 with tumor-targeting antibodies, such as rituximab, further enhances Hu5F9-G4's anticancer effects via ADCP. Clinical trials have additionally demonstrated that Hu5F9-G4, in combination with rituximab, produced objective responses in patients whose diffuse large B cell lymphomas had developed resistance to rituximab and chemotherapy. These studies led us to hypothesize that combining Hu5F9-G4 with trastuzumab would produce an anticancer effect in antibody-dependent cellular cytotoxicity (ADCC)-tolerant HER2 breast cancer. This combination significantly suppressed the growth of ADCC-tolerant HER2 breast cancers via Fc-dependent ADCP. Our study demonstrates that combining trastuzumab and Hu5F9-G4 represents a potential new treatment option for HER2 breast cancer patients, even for patients whose tumors have progressed after trastuzumab.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1073/pnas.2026849118DOI Listing
July 2021

CD47 blockade reduces the pathologic features of experimental cerebral malaria and promotes survival of hosts with infection.

Proc Natl Acad Sci U S A 2021 Mar;118(11)

Institute for Stem Cell Biology and Regenerative Medicine, Stanford University School of Medicine, Stanford, CA 94305;

CD47 is an antiphagocytic "don't eat me" signal that inhibits programmed cell removal of self. As red blood cells (RBCs) age they lose CD47 expression and become susceptible to programmed cell removal by macrophages. CD47 mice infected with , which exhibits an age-based preference for young RBCs, were previously demonstrated to be highly resistant to malaria infection. Our study sought to test the therapeutic benefit of CD47 blockade on ameliorating the clinical syndromes of experimental cerebral malaria (ECM), using the ANKA () murine model. In vitro we tested the effect of anti-CD47 mAb on infected RBC phagocytosis and found that anti-CD47 treatment significantly increased clearance of -infected RBCs. Infection of C57BL/6 mice with is lethal and mice succumb to the clinical syndromes of CM between days 6 and 10 postinfection. Strikingly, treatment with anti-CD47 resulted in increased survival during the cerebral phase of infection. Anti-CD47-treated mice had increased lymphocyte counts in the peripheral blood and increased circulating levels of IFN-γ, TNF-α, and IL-22. Despite increased circulating levels of inflammatory cytokines, anti-CD47-treated mice had reduced pathological features in the brain. Survival of ECM in anti-CD47-treated mice was correlated with reduced cellular accumulation in the cerebral vasculature, improved blood-brain barrier integrity, and reduced cytotoxic activity of infiltrating CD8 T cells. These results demonstrate the therapeutic benefit of anti-CD47 to reduce morbidity in a lethal model of ECM, which may have implications for preventing mortality in young African children who are the highest casualties of CM.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1073/pnas.1907653118DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7980459PMC
March 2021

Overexpression of CD47 is associated with brain overgrowth and 16p11.2 deletion syndrome.

Proc Natl Acad Sci U S A 2021 Apr;118(15)

Department of Psychiatry and Behavioral Sciences, Stanford University School of Medicine, Stanford, CA 94305;

Copy number variation (CNV) at the 16p11.2 locus is associated with neuropsychiatric disorders, such as autism spectrum disorder and schizophrenia. CNVs of the 16p gene can manifest in opposing head sizes. Carriers of 16p11.2 deletion tend to have macrocephaly (or brain enlargement), while those with 16p11.2 duplication frequently have microcephaly. Increases in both gray and white matter volume have been observed in brain imaging studies in 16p11.2 deletion carriers with macrocephaly. Here, we use human induced pluripotent stem cells (hiPSCs) derived from controls and subjects with 16p11.2 deletion and 16p11.2 duplication to understand the underlying mechanisms regulating brain overgrowth. To model both gray and white matter, we differentiated patient-derived iPSCs into neural progenitor cells (NPCs) and oligodendrocyte progenitor cells (OPCs). In both NPCs and OPCs, we show that CD47 (a "don't eat me" signal) is overexpressed in the 16p11.2 deletion carriers contributing to reduced phagocytosis both in vitro and in vivo. Furthermore, 16p11.2 deletion NPCs and OPCs up-regulate cell surface expression of calreticulin (a prophagocytic "eat me" signal) and its binding sites, indicating that these cells should be phagocytosed but fail to be eliminated due to elevations in CD47. Treatment of 16p11.2 deletion NPCs and OPCs with an anti-CD47 antibody to block CD47 restores phagocytosis to control levels. While the CD47 pathway is commonly implicated in cancer progression, we document a role for CD47 in psychiatric disorders associated with brain overgrowth.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1073/pnas.2005483118DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8053942PMC
April 2021

Global analysis of shared T cell specificities in human non-small cell lung cancer enables HLA inference and antigen discovery.

Immunity 2021 Mar;54(3):586-602.e8

Institute for Immunity, Transplantation and Infection, Stanford University, Stanford, CA 94305, USA.

To identify disease-relevant T cell receptors (TCRs) with shared antigen specificity, we analyzed 778,938 TCRβ chain sequences from 178 non-small cell lung cancer patients using the GLIPH2 (grouping of lymphocyte interactions with paratope hotspots 2) algorithm. We identified over 66,000 shared specificity groups, of which 435 were clonally expanded and enriched in tumors compared to adjacent lung. The antigenic epitopes of one such tumor-enriched specificity group were identified using a yeast peptide-HLA A02:01 display library. These included a peptide from the epithelial protein TMEM161A, which is overexpressed in tumors and cross-reactive epitopes from Epstein-Barr virus and E. coli. Our findings suggest that this cross-reactivity may underlie the presence of virus-specific T cells in tumor infiltrates and that pathogen cross-reactivity may be a feature of multiple cancers. The approach and analytical pipelines generated in this work, as well as the specificity groups defined here, present a resource for understanding the T cell response in cancer.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1016/j.immuni.2021.02.014DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7960510PMC
March 2021

Reactivation of the pluripotency program precedes formation of the cranial neural crest.

Science 2021 02;371(6529)

Department of Chemical and Systems Biology, Stanford University School of Medicine, Stanford, CA 94305, USA.

During development, cells progress from a pluripotent state to a more restricted fate within a particular germ layer. However, cranial neural crest cells (CNCCs), a transient cell population that generates most of the craniofacial skeleton, have much broader differentiation potential than their ectodermal lineage of origin. Here, we identify a neuroepithelial precursor population characterized by expression of canonical pluripotency transcription factors that gives rise to CNCCs and is essential for craniofacial development. Pluripotency factor is transiently reactivated in CNCCs and is required for the subsequent formation of ectomesenchyme. Furthermore, open chromatin landscapes of Oct4 CNCC precursors resemble those of epiblast stem cells, with additional features suggestive of priming for mesenchymal programs. We propose that CNCCs expand their developmental potential through a transient reacquisition of molecular signatures of pluripotency.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1126/science.abb4776DOI Listing
February 2021

Sexual and asexual development: two distinct programs producing the same tunicate.

Cell Rep 2021 Jan;34(4):108681

Institute for Stem Cell Biology and Regenerative Medicine, and Ludwig Center, Stanford University School of Medicine, Stanford, CA 94305, USA; Department of Biology, Stanford University, Hopkins Marine Station, Pacific Grove, CA 93950, USA; Chan Zuckerberg Biohub, San Francisco, CA 94158, USA. Electronic address:

Colonial tunicates are the only chordate that possess two distinct developmental pathways to produce an adult body: either sexually through embryogenesis or asexually through a stem cell-mediated renewal termed blastogenesis. Using the colonial tunicate Botryllus schlosseri, we combine transcriptomics and microscopy to build an atlas of the molecular and morphological signatures at each developmental stage for both pathways. The general molecular profiles of these processes are largely distinct. However, the relative timing of organogenesis and ordering of tissue-specific gene expression are conserved. By comparing the developmental pathways of B. schlosseri with other chordates, we identify hundreds of putative transcription factors with conserved temporal expression. Our findings demonstrate that convergent morphology need not imply convergent molecular mechanisms but that it showcases the importance that tissue-specific stem cells and transcription factors play in producing the same mature body through different pathways.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1016/j.celrep.2020.108681DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7949349PMC
January 2021

Restoring metabolism of myeloid cells reverses cognitive decline in ageing.

Nature 2021 02 20;590(7844):122-128. Epub 2021 Jan 20.

Department of Neurology and Neurological Sciences, Stanford University School of Medicine, Stanford, CA, USA.

Ageing is characterized by the development of persistent pro-inflammatory responses that contribute to atherosclerosis, metabolic syndrome, cancer and frailty. The ageing brain is also vulnerable to inflammation, as demonstrated by the high prevalence of age-associated cognitive decline and Alzheimer's disease. Systemically, circulating pro-inflammatory factors can promote cognitive decline, and in the brain, microglia lose the ability to clear misfolded proteins that are associated with neurodegeneration. However, the underlying mechanisms that initiate and sustain maladaptive inflammation with ageing are not well defined. Here we show that in ageing mice myeloid cell bioenergetics are suppressed in response to increased signalling by the lipid messenger prostaglandin E (PGE), a major modulator of inflammation. In ageing macrophages and microglia, PGE signalling through its EP2 receptor promotes the sequestration of glucose into glycogen, reducing glucose flux and mitochondrial respiration. This energy-deficient state, which drives maladaptive pro-inflammatory responses, is further augmented by a dependence of aged myeloid cells on glucose as a principal fuel source. In aged mice, inhibition of myeloid EP2 signalling rejuvenates cellular bioenergetics, systemic and brain inflammatory states, hippocampal synaptic plasticity and spatial memory. Moreover, blockade of peripheral myeloid EP2 signalling is sufficient to restore cognition in aged mice. Our study suggests that cognitive ageing is not a static or irrevocable condition but can be reversed by reprogramming myeloid glucose metabolism to restore youthful immune functions.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1038/s41586-020-03160-0DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8274816PMC
February 2021

Hoxb5 defines the heterogeneity of self-renewal capacity in the hematopoietic stem cell compartment.

Biochem Biophys Res Commun 2021 02 5;539:34-41. Epub 2021 Jan 5.

RIKEN Center for Biosystems Dynamics Research (BDR), Kobe, Hyogo, 650-0047, Japan. Electronic address:

Self-renewal and multipotency are essential functions of hematopoietic stem cells (HSCs). To maintain homeostatic hematopoiesis, functionally uniform HSCs have been thought to be an ideal cell-of-origin. Recent technological advances in the field have allowed us to analyze HSCs with single cell resolution and implicate that functional heterogeneity may exist even within the highly purified HSC compartment. However, due in part to the technical limitations of analyzing extremely rare populations and our incomplete understanding of HSC biology, neither the biological meaning of why heterogeneity exists nor the precise mechanism of how heterogeneity is determined within the HSC compartment is entirely known. Here we show the first evidence that self-renewal capacity varies with the degree of replication stress dose and results in heterogeneity within the HSC compartment. Using the Hoxb5-reporter mouse line which enables us to distinguish between long-term (LT)-HSCs and short-term (ST)-HSCs, we have found that ST-HSCs quickly lose self-renewal capacity under high stress environments but can maintain self-renewal under low stress environments for long periods of time. Critically, exogeneous Hoxb5 expression confers protection against loss of self-renewal to Hoxb5-negative HSCs and can partially alter the cell fate of ST-HSCs to that of LT-HSCs. Our results demonstrate that Hoxb5 imparts functional heterogeneity in the HSC compartment by regulating self-renewal capacity. Additionally, Hoxb5-positive HSCs may exist as fail-safe system to protect from the exhaustion of HSCs throughout an organism's lifespan.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1016/j.bbrc.2020.12.077DOI Listing
February 2021

Semaphorin 3A mediated brain tumor stem cell proliferation and invasion in EGFRviii mutant gliomas.

BMC Cancer 2020 Dec 10;20(1):1213. Epub 2020 Dec 10.

Department of Neurologic Surgery, Mayo Clinic, Rochester, MN, 55905, USA.

Background: Glioblastoma multiforme (GBM) is the most common primary brain tumor in adults, with a median survival of approximately 15 months. Semaphorin 3A (Sema3A), known for its axon guidance and antiangiogenic properties, has been implicated in GBM growth. We hypothesized that Sema3A directly inhibits brain tumor stem cell (BTSC) proliferation and drives invasion via Neuropilin 1 (Nrp1) and Plexin A1 (PlxnA1) receptors.

Methods: GBM BTSC cell lines were assayed by immunostaining and PCR for levels of Semaphorin 3A (Sema3A) and its receptors Nrp1 and PlxnA1. Quantitative BrdU, cell cycle and propidium iodide labeling assays were performed following exogenous Sema3A treatment. Quantitative functional 2-D and 3-D invasion assays along with shRNA lentiviral knockdown of Nrp1 and PlxnA1 are also shown. In vivo flank studies comparing tumor growth of knockdown versus control BTSCs were performed. Statistics were performed using GraphPad Prism v7.

Results: Immunostaining and PCR analysis revealed that BTSCs highly express Sema3A and its receptors Nrp1 and PlxnA1, with expression of Nrp1 in the CD133 positive BTSCs, and absence in differentiated tumor cells. Treatment with exogenous Sema3A in quantitative BrdU, cell cycle, and propidium iodide labeling assays demonstrated that Sema3A significantly inhibited BTSC proliferation without inducing cell death. Quantitative functional 2-D and 3-D invasion assays showed that treatment with Sema3A resulted in increased invasion. Using shRNA lentiviruses, knockdown of either NRP1 or PlxnA1 receptors abrogated Sema3A antiproliferative and pro-invasive effects. Interestingly, loss of the receptors mimicked Sema3A effects, inhibiting BTSC proliferation and driving invasion. Furthermore, in vivo studies comparing tumor growth of knockdown and control infected BTSCs implanted into the flanks of nude mice confirmed the decrease in proliferation with receptor KD.

Conclusions: These findings demonstrate the importance of Sema3A signaling in GBM BTSC proliferation and invasion, and its potential as a therapeutic target.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1186/s12885-020-07694-4DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7727139PMC
December 2020

Proteomic analysis of young and old mouse hematopoietic stem cells and their progenitors reveals post-transcriptional regulation in stem cells.

Elife 2020 11 25;9. Epub 2020 Nov 25.

Institute for Stem Cell Biology and Regenerative Medicine, Stanford University School of Medicine, Stanford, United States.

The balance of hematopoietic stem cell (HSC) self-renewal and differentiation is critical for a healthy blood supply; imbalances underlie hematological diseases. The importance of HSCs and their progenitors have led to their extensive characterization at genomic and transcriptomic levels. However, the proteomics of hematopoiesis remains incompletely understood. Here we report a proteomics resource from mass spectrometry of mouse young adult and old adult mouse HSCs, multipotent progenitors and oligopotent progenitors; 12 cell types in total. We validated differential protein levels, including confirmation that Dnmt3a protein levels are undetected in young adult mouse HSCs until forced into cycle. Additionally, through integrating proteomics and RNA-sequencing datasets, we identified a subset of genes with apparent post-transcriptional repression in young adult mouse HSCs. In summary, we report proteomic coverage of young and old mouse HSCs and progenitors, with broader implications for understanding mechanisms for stem cell maintenance, niche interactions and fate determination.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.7554/eLife.62210DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7688314PMC
November 2020

A molecular cell atlas of the human lung from single-cell RNA sequencing.

Nature 2020 11 18;587(7835):619-625. Epub 2020 Nov 18.

Department of Biochemistry, Howard Hughes Medical Institute, Stanford University School of Medicine, Stanford, CA, USA.

Although single-cell RNA sequencing studies have begun to provide compendia of cell expression profiles, it has been difficult to systematically identify and localize all molecular cell types in individual organs to create a full molecular cell atlas. Here, using droplet- and plate-based single-cell RNA sequencing of approximately 75,000 human cells across all lung tissue compartments and circulating blood, combined with a multi-pronged cell annotation approach, we create an extensive cell atlas of the human lung. We define the gene expression profiles and anatomical locations of 58 cell populations in the human lung, including 41 out of 45 previously known cell types and 14 previously unknown ones. This comprehensive molecular atlas identifies the biochemical functions of lung cells and the transcription factors and markers for making and monitoring them; defines the cell targets of circulating hormones and predicts local signalling interactions and immune cell homing; and identifies cell types that are directly affected by lung disease genes and respiratory viruses. By comparing human and mouse data, we identified 17 molecular cell types that have been gained or lost during lung evolution and others with substantially altered expression profiles, revealing extensive plasticity of cell types and cell-type-specific gene expression during organ evolution including expression switches between cell types. This atlas provides the molecular foundation for investigating how lung cell identities, functions and interactions are achieved in development and tissue engineering and altered in disease and evolution.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1038/s41586-020-2922-4DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7704697PMC
November 2020

Effects of Ultra-high doserate FLASH Irradiation on the Tumor Microenvironment in Lewis Lung Carcinoma: Role of Myosin Light Chain.

Int J Radiat Oncol Biol Phys 2021 04 10;109(5):1440-1453. Epub 2020 Nov 10.

College of Veterinary Medicine, Seoul National University, Seoul, Korea. Electronic address:

Purpose: To investigate whether the vascular collapse in tumors by conventional dose rate (CONV) irradiation (IR) would also occur by the ultra-high dose rate FLASH IR.

Methods And Materials: Lewis lung carcinoma (LLC) cells were subcutaneously implanted in mice. This was followed by CONV or FLASH IR at 15 Gy. Tumors were harvested at 6 or 48 hours after IR and stained for CD31, phosphorylated myosin light chain (p-MLC), γH2AX (a surrogate marker for DNA double strand break), intracellular reactive oxygen species (ROS), or immune cells such as myeloid and CD8α T cells. Cell lines were irradiated with CONV IR for Western blot analyses. ML-7 was intraperitoneally administered daily to LLC-bearing mice for 7 days before 15 Gy CONV IR. Tumors were similarly harvested and analyzed.

Results: By immunostaining, we observed that CONV IR at 6 hours resulted in constricted vessel morphology, increased expression of p-MLC, and much higher numbers of γH2AX-positive cells in tumors, which were not observed with FLASH IR. Mechanistically, MLC activation by ROS is unlikely, because FLASH IR produced significantly more ROS than CONV IR in tumors. In vitro studies demonstrated that ML-7, an inhibitor of MLC kinase, abrogated IR-induced γH2AX formation and disappearance kinetics. Lastly, we observed that CONV IR when combined with ML-7 produced some effects similar to FLASH IR, including reduction in the vasculature collapse, fewer γH2AX-positive cells, and increased immune cell influx to the tumors.

Conclusions: FLASH IR produced novel changes in the tumor microenvironment that were not observed with CONV IR. We believe that MLC activation in tumors may be responsible for some of the microenvironmental changes differentially regulated between CONV and FLASH IR.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1016/j.ijrobp.2020.11.012DOI Listing
April 2021

Articular cartilage regeneration by activated skeletal stem cells.

Nat Med 2020 10 17;26(10):1583-1592. Epub 2020 Aug 17.

Institute for Stem Cell Biology and Regenerative Medicine, Stanford University School of Medicine, Stanford, CA, USA.

Osteoarthritis (OA) is a degenerative disease resulting in irreversible, progressive destruction of articular cartilage. The etiology of OA is complex and involves a variety of factors, including genetic predisposition, acute injury and chronic inflammation. Here we investigate the ability of resident skeletal stem-cell (SSC) populations to regenerate cartilage in relation to age, a possible contributor to the development of osteoarthritis. We demonstrate that aging is associated with progressive loss of SSCs and diminished chondrogenesis in the joints of both mice and humans. However, a local expansion of SSCs could still be triggered in the chondral surface of adult limb joints in mice by stimulating a regenerative response using microfracture (MF) surgery. Although MF-activated SSCs tended to form fibrous tissues, localized co-delivery of BMP2 and soluble VEGFR1 (sVEGFR1), a VEGF receptor antagonist, in a hydrogel skewed differentiation of MF-activated SSCs toward articular cartilage. These data indicate that following MF, a resident stem-cell population can be induced to generate cartilage for treatment of localized chondral disease in OA.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1038/s41591-020-1013-2DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7704061PMC
October 2020

Upregulation of CD47 Is a Host Checkpoint Response to Pathogen Recognition.

mBio 2020 06 23;11(3). Epub 2020 Jun 23.

Department of Gastroenterology and Hepatology, Stanford University School of Medicine, Stanford, California, USA.

It is well understood that the adaptive immune response to infectious agents includes a modulating suppressive component as well as an activating component. We now show that the very early innate response also has an immunosuppressive component. Infected cells upregulate the CD47 "don't eat me" signal, which slows the phagocytic uptake of dying and viable cells as well as downstream antigen-presenting cell (APC) functions. A CD47 mimic that acts as an essential virulence factor is encoded by all poxviruses, but CD47 expression on infected cells was found to be upregulated even by pathogens, including severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), that encode no mimic. CD47 upregulation was revealed to be a host response induced by the stimulation of both endosomal and cytosolic pathogen recognition receptors (PRRs). Furthermore, proinflammatory cytokines, including those found in the plasma of hepatitis C patients, upregulated CD47 on uninfected dendritic cells, thereby linking innate modulation with downstream adaptive immune responses. Indeed, results from antibody-mediated CD47 blockade experiments as well as CD47 knockout mice revealed an immunosuppressive role for CD47 during infections with lymphocytic choriomeningitis virus and Since CD47 blockade operates at the level of pattern recognition receptors rather than at a pathogen or antigen-specific level, these findings identify CD47 as a novel potential immunotherapeutic target for the enhancement of immune responses to a broad range of infectious agents. Immune responses to infectious agents are initiated when a pathogen or its components bind to pattern recognition receptors (PRRs). PRR binding sets off a cascade of events that activates immune responses. We now show that, in addition to activating immune responses, PRR signaling also initiates an immunosuppressive response, probably to limit inflammation. The importance of the current findings is that blockade of immunomodulatory signaling, which is mediated by the upregulation of the CD47 molecule, can lead to enhanced immune responses to any pathogen that triggers PRR signaling. Since most or all pathogens trigger PRRs, CD47 blockade could be used to speed up and strengthen both innate and adaptive immune responses when medically indicated. Such immunotherapy could be done without a requirement for knowing the HLA type of the individual, the specific antigens of the pathogen, or, in the case of bacterial infections, the antimicrobial resistance profile.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1128/mBio.01293-20DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7315125PMC
June 2020

Clonally expanding smooth muscle cells promote atherosclerosis by escaping efferocytosis and activating the complement cascade.

Proc Natl Acad Sci U S A 2020 07 15;117(27):15818-15826. Epub 2020 Jun 15.

Division of Vascular Surgery, Department of Surgery, Stanford University School of Medicine, Stanford, CA 94305;

Atherosclerosis is the process underlying heart attack and stroke. Despite decades of research, its pathogenesis remains unclear. Dogma suggests that atherosclerotic plaques expand primarily via the accumulation of cholesterol and inflammatory cells. However, recent evidence suggests that a substantial portion of the plaque may arise from a subset of "dedifferentiated" vascular smooth muscle cells (SMCs) which proliferate in a clonal fashion. Herein we use multicolor lineage-tracing models to confirm that the mature SMC can give rise to a hyperproliferative cell which appears to promote inflammation via elaboration of complement-dependent anaphylatoxins. Despite being extensively opsonized with prophagocytic complement fragments, we find that this cell also escapes immune surveillance by neighboring macrophages, thereby exacerbating its relative survival advantage. Mechanistic studies indicate this phenomenon results from a generalized opsonin-sensing defect acquired by macrophages during polarization. This defect coincides with the noncanonical up-regulation of so-called don't eat me molecules on inflamed phagocytes, which reduces their capacity for programmed cell removal (PrCR). Knockdown or knockout of the key antiphagocytic molecule CD47 restores the ability of macrophages to sense and clear opsonized targets in vitro, allowing for potent and targeted suppression of clonal SMC expansion in the plaque in vivo. Because integrated clinical and genomic analyses indicate that similar pathways are active in humans with cardiovascular disease, these studies suggest that the clonally expanding SMC may represent a translational target for treating atherosclerosis.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1073/pnas.2006348117DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7354942PMC
July 2020

Targeting macrophage checkpoint inhibitor SIRPα for anticancer therapy.

JCI Insight 2020 06 18;5(12). Epub 2020 Jun 18.

Forty Seven Inc., Menlo Park, California, USA.

The CD47/signal regulatory protein α (Cd47/SIRPα)interaction provides a macrophage immune checkpoint pathway that plays a critical role in cancer immune evasion across multiple cancers. Here, we report the engineering of a humanized anti-SIRPα monoclonal antibody (1H9) for antibody target cancer therapy. 1H9 has broad activity across a wide range of SIRPα variants. Binding of 1H9 to SIRPα blocks its interaction with CD47, thereby promoting macrophage-mediated phagocytosis of cancer cells. Preclinical studies in vitro and in vivo demonstrate that 1H9 synergizes with other therapeutic antibodies to promote phagocytosis of tumor cells and inhibit tumor growth in both syngeneic and xenograft tumor models, leading to survival benefit. Thus, 1H9 can potentially act as a universal agent to enhance therapeutic efficacy when used in combination with most tumor-targeting antibodies. We report a comparison of anti-SIRPα and anti-CD47 antibodies in CD47/SIRPα double-humanized mice and found that 1H9 exhibits a substantially reduced antigen sink effect due to the limited tissue distribution of SIRPα expression. Toxicokinetic studies in nonhuman primates show that 1H9 is well tolerated, with no treatment-related adverse effects noted. These data highlight the clinical potential of 1H9 as a pan-therapeutic with the desired properties when used in combination with tumor-targeting antibodies.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1172/jci.insight.134728DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7406266PMC
June 2020

Immunotherapeutic Blockade of CD47 Inhibitory Signaling Enhances Innate and Adaptive Immune Responses to Viral Infection.

Cell Rep 2020 04;31(2):107494

Laboratory of Persistent Viral Diseases, Rocky Mountain Laboratories, NIAID, NIH, Hamilton, MT 59840, USA. Electronic address:

Paradoxically, early host responses to infection include the upregulation of the antiphagocytic molecule, CD47. This suggests that CD47 blockade could enhance antigen presentation and subsequent immune responses. Indeed, mice treated with anti-CD47 monoclonal antibody following lymphocytic choriomeningitis virus infections show increased activation of both macrophages and dendritic cells (DCs), enhancement of the kinetics and potency of CD8 T cell responses, and significantly improved virus control. Treatment efficacy is critically dependent on both APCs and CD8 T cells. In preliminary results from one of two cohorts of humanized mice infected with HIV-1 for 6 weeks, CD47 blockade reduces plasma p24 levels and restores CD4 T cell counts. The results indicate that CD47 blockade not only enhances the function of innate immune cells but also links to adaptive immune responses through improved APC function. As such, immunotherapy by CD47 blockade may have broad applicability to treat a wide range of infectious diseases.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1016/j.celrep.2020.03.058DOI Listing
April 2020

Therapeutic Targeting of the Macrophage Immune Checkpoint CD47 in Myeloid Malignancies.

Front Oncol 2019 22;9:1380. Epub 2020 Jan 22.

Institute for Stem Cell Biology and Regenerative Medicine, Stanford University, Palo Alto, CA, United States.

In recent years, immunotherapies have been clinically investigated in AML and other myeloid malignancies. While most of these are focused on stimulating the adaptive immune system (including T cell checkpoint inhibitors), several key approaches targeting the innate immune system have been identified. Macrophages are a key cell type in the innate immune response with CD47 being identified as a dominant macrophage checkpoint. CD47 is a "do not eat me" signal, overexpressed in myeloid malignancies that leads to tumor evasion of phagocytosis by macrophages. Blockade of CD47 leads to engulfment of leukemic cells and therapeutic elimination. Pre-clinical data has demonstrated robust anti-cancer activity in multiple hematologic malignancies including AML and myelodysplastic syndrome (MDS). In addition, clinical studies have been underway with CD47 targeting agents in both AML and MDS as monotherapy and in combination. This review will describe the role of CD47 in myeloid malignancies and pre-clinical data supporting CD47 targeting. In addition, initial clinical data of CD47 targeting in AML/MDS will be reviewed, and including the first-in-class anti-CD47 antibody magrolimab.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.3389/fonc.2019.01380DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6990910PMC
January 2020

Pro-efferocytic nanoparticles are specifically taken up by lesional macrophages and prevent atherosclerosis.

Nat Nanotechnol 2020 02 27;15(2):154-161. Epub 2020 Jan 27.

Department of Surgery, Division of Vascular Surgery, Stanford University School of Medicine, Stanford, CA, USA.

Atherosclerosis is the process that underlies heart attack and stroke. A characteristic feature of the atherosclerotic plaque is the accumulation of apoptotic cells in the necrotic core. Prophagocytic antibody-based therapies are currently being explored to stimulate the phagocytic clearance of apoptotic cells; however, these therapies can cause off-target clearance of healthy tissues, which leads to toxicities such as anaemia. Here we developed a macrophage-specific nanotherapy based on single-walled carbon nanotubes loaded with a chemical inhibitor of the antiphagocytic CD47-SIRPα signalling axis. We demonstrate that these single-walled carbon nanotubes accumulate within the atherosclerotic plaque, reactivate lesional phagocytosis and reduce the plaque burden in atheroprone apolipoprotein-E-deficient mice without compromising safety, and thereby overcome a key translational barrier for this class of drugs. Single-cell RNA sequencing analysis reveals that prophagocytic single-walled carbon nanotubes decrease the expression of inflammatory genes linked to cytokine and chemokine pathways in lesional macrophages, which demonstrates the potential of 'Trojan horse' nanoparticles to prevent atherosclerotic cardiovascular disease.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1038/s41565-019-0619-3DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7254969PMC
February 2020

Evolutionary perspective on the hematopoietic system through a colonial chordate: allogeneic immunity and hematopoiesis.

Curr Opin Immunol 2020 02 16;62:91-98. Epub 2020 Jan 16.

Institute for Stem Cell Biology and Regenerative Medicine, and Ludwig Center for Cancer Stem Cell Research, Stanford University School of Medicine, CA, USA; Hopkins Marine Station, Stanford University, Pacific Grove, CA 93950, USA; Chan Zuckerberg Biohub, San Francisco CA 94158, USA. Electronic address:

Evolution and selection have shaped diverse immune systems throughout phylogeny, the vast majority of which remain unexplored. Botryllus schlosseri is a colonial tunicate, a sister group to vertebrates, that develops as a chordate, then metamorphoses to an asexually reproductive invertebrate that every week makes the same body plan from budded stem cells. Genetically distinct B. schlosseri colonies can fuse to form a chimera, or reject each other based on allogeneic recognition. In chimeras, circulating germline and somatic stem cells participate in development; stem cells compete in all individuals in the fused colonies, with rejection preventing germline parasitism. Here we review the isolation and characterization of B. schlosseri hematopoietic stem cells (HSC) and their niches, and the role of the immune effector cells in allorecognition.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1016/j.coi.2019.12.006DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7136747PMC
February 2020

Heme oxygenase-1 deficiency triggers exhaustion of hematopoietic stem cells.

EMBO Rep 2020 02 29;21(2):e47895. Epub 2019 Dec 29.

Department of Medical Biotechnology, Faculty of Biochemistry, Biophysics and Biotechnology, Jagiellonian University, Krakow, Poland.

While intrinsic changes in aging hematopoietic stem cells (HSCs) are well characterized, it remains unclear how extrinsic factors affect HSC aging. Here, we demonstrate that cells in the niche-endothelial cells (ECs) and CXCL12-abundant reticular cells (CARs)-highly express the heme-degrading enzyme, heme oxygenase 1 (HO-1), but then decrease its expression with age. HO-1-deficient animals (HO-1 ) have altered numbers of ECs and CARs that produce less hematopoietic factors. HSCs co-cultured in vitro with HO-1 mesenchymal stromal cells expand, but have altered kinetic of growth and differentiation of derived colonies. HSCs from young HO-1 animals have reduced quiescence and regenerative potential. Young HO-1 HSCs exhibit features of premature exhaustion on the transcriptional and functional level. HO-1 HSCs transplanted into HO-1 recipients exhaust their regenerative potential early and do not reconstitute secondary recipients. In turn, transplantation of HO-1 HSCs to the HO-1 recipients recovers the regenerative potential of HO-1 HSCs and reverses their transcriptional alterations. Thus, HSC-extrinsic activity of HO-1 prevents HSCs from premature exhaustion and may restore the function of aged HSCs.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.15252/embr.201947895DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7001511PMC
February 2020

Neogenin-1 distinguishes between myeloid-biased and balanced mouse long-term hematopoietic stem cells.

Proc Natl Acad Sci U S A 2019 12 21;116(50):25115-25125. Epub 2019 Nov 21.

Institute for Stem Cell Biology and Regenerative Medicine, Stanford University, Stanford, CA 94305;

Hematopoietic stem cells (HSCs) self-renew and generate all blood cells. Recent studies with single cell transplants and lineage tracing suggest that adult HSCs are diverse in their reconstitution and lineage potentials. However, prospective isolation of these subpopulations has remained challenging. Here, we identify Neogenin-1 (NEO1) as a unique surface marker on a fraction of mouse HSCs labeled with , a specific reporter of long-term HSCs (LT-HSCs). We show that NEO1 LT-HSCs expand with age and respond to myeloablative stress in young mice while NEO1 LT-HSCs exhibit no significant change in number. Furthermore, NEO1 LT-HSCs are more often in the G/S cell cycle phase compared to NEO1 LT-HSCs in both young and old bone marrow. Upon serial transplantation, NEO1 LT-HSCs exhibit myeloid-biased differentiation and reduced reconstitution while NEO1 LT-HSCs are lineage-balanced and stably reconstitute recipients. Gene expression analysis reveals erythroid and myeloid priming in the NEO1 fraction and association of quiescence and self-renewal-related transcription factors with NEO1 LT-HSCs. Finally, transplanted NEO1 LT-HSCs rarely generate NEO1 LT-HSCs while NEO1 LT-HSCs repopulate both LT-HSC fractions. This supports a model in which dormant, balanced NEO1 LT-HSCs can hierarchically precede active, myeloid-biased NEO1 LT-HSCs.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1073/pnas.1911024116DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6911217PMC
December 2019

The Ban on US Government Funding Research Using Human Fetal Tissues: How Does This Fit with the NIH Mission to Advance Medical Science for the Benefit of the Citizenry?

Stem Cell Reports 2019 11;13(5):777-786

Institute for Stem Cell Biology and Regenerative Medicine and Ludwig Center for Cancer Stem Cell Research, Stanford University, Stanford, CA, USA. Electronic address:

Some have argued that human fetal tissue research is unnecessary and/or immoral. Recently, the Trump administration has taken the drastic--and we believe misguided--step to effectively ban government-funded research on fetal tissue altogether. In this article, we show that entire lines of research and their clinical outcomes would not have progressed had fetal tissue been unavailable. We argue that this research has been carried out in a manner that is ethical and legal, and that it has provided knowledge that has saved lives, particularly those of pregnant women, their unborn fetuses, and newborns. We believe that those who support a ban on the use of fetal tissue are halting medical progress and therefore endangering the health and lives of many, and for this they should accept responsibility. At the very least, we challenge them to be true to their beliefs: if they wish to short-circuit a scientific process that has led to medical advances, they should pledge to not accept for themselves the health benefits that such advances provide.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1016/j.stemcr.2019.10.003DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6895704PMC
November 2019

Dysregulated integrin αVβ3 and CD47 signaling promotes joint inflammation, cartilage breakdown, and progression of osteoarthritis.

JCI Insight 2019 09 19;4(18). Epub 2019 Sep 19.

Division of Immunology and Rheumatology, Stanford University School of Medicine, Stanford, California, USA.

Osteoarthritis (OA) is the leading cause of joint failure, yet the underlying mechanisms remain elusive, and no approved therapies that slow progression exist. Dysregulated integrin function was previously implicated in OA pathogenesis. However, the roles of integrin αVβ3 and the integrin-associated receptor CD47 in OA remain largely unknown. Here, transcriptomic and proteomic analyses of human and murine osteoarthritic tissues revealed dysregulated expression of αVβ3, CD47, and their ligands. Using genetically deficient mice and pharmacologic inhibitors, we showed that αVβ3, CD47, and the downstream signaling molecules Fyn and FAK are crucial to OA pathogenesis. MicroPET/CT imaging of a mouse model showed elevated ligand-binding capacities of integrin αVβ3 and CD47 in osteoarthritic joints. Further, our in vitro studies demonstrated that chondrocyte breakdown products, derived from articular cartilage of individuals with OA, induced αVβ3/CD47-dependent expression of inflammatory and degradative mediators, and revealed the downstream signaling network. Our findings identify a central role for dysregulated αVβ3 and CD47 signaling in OA pathogenesis and suggest that activation of αVβ3 and CD47 signaling in many articular cell types contributes to inflammation and joint destruction in OA. Thus, the data presented here provide a rationale for targeting αVβ3, CD47, and their signaling pathways as a disease-modifying therapy.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1172/jci.insight.128616DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6795293PMC
September 2019

Neutrophil and monocyte kinetics play critical roles in mouse peritoneal adhesion formation.

Blood Adv 2019 09;3(18):2713-2721

Institute for Stem Cell Biology and Regenerative Medicine and.

Peritoneal adhesions are pathological fibroses that ensnare organs after abdominal surgery. This dense connective tissue can cause small bowel obstruction, female infertility, and chronic abdominal pain. The pathogenesis of adhesions is a fibrotic response to tissue damage coordinated between mesothelial cells, fibroblasts, and immune cells. We have previously demonstrated that peritoneal adhesions are a consequence of mechanical injury to the mesothelial layer sustained during surgery. Neutrophils are among the first leukocytes involved in the early response to tissue damage. Here, we show that when subjected to mechanical stress, activated mesothelial cells directly recruit neutrophils and monocytes through upregulation of chemokines such as CXCL1 and monocyte chemoattractant protein 1 (MCP-1). We find that neutrophils within the adhesion sites undergo cell death and form neutrophil extracellular traps (NETosis) that contribute to pathogenesis. Conversely, tissue-resident macrophages were profoundly depleted throughout the disease time course. We show that this is distinct from traditional inflammatory kinetics such as after sham surgery or chemically induced peritonitis, and suggest that adhesions result from a primary difference in inflammatory kinetics. We find that transient depletion of circulating neutrophils significantly decreases adhesion burden, and further recruitment of monocytes with thioglycolate or MCP-1 also improves outcomes. Our findings suggest that the combination of neutrophil depletion and monocyte recruitment is sufficient to prevent adhesion formation, thus providing insight for potential clinical interventions.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1182/bloodadvances.2018024026DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6759736PMC
September 2019

Phagocytosis checkpoints as new targets for cancer immunotherapy.

Nat Rev Cancer 2019 10 28;19(10):568-586. Epub 2019 Aug 28.

Institute for Stem Cell Biology and Regenerative Medicine, Stanford University, Stanford, CA, USA.

Cancer immunotherapies targeting adaptive immune checkpoints have substantially improved patient outcomes across multiple metastatic and treatment-refractory cancer types. However, emerging studies have demonstrated that innate immune checkpoints, which interfere with the detection and clearance of malignant cells through phagocytosis and suppress innate immune sensing, also have a key role in tumour-mediated immune escape and might, therefore, be potential targets for cancer immunotherapy. Indeed, preclinical studies and early clinical data have established the promise of targeting phagocytosis checkpoints, such as the CD47-signal-regulatory protein α (SIRPα) axis, either alone or in combination with other cancer therapies. In this Review, we highlight the current understanding of how cancer cells evade the immune system by disrupting phagocytic clearance and the effect of phagocytosis checkpoint blockade on induction of antitumour immune responses. Given the role of innate immune cells in priming adaptive immune responses, an improved understanding of the tumour-intrinsic processes that inhibit essential immune surveillance processes, such as phagocytosis and innate immune sensing, could pave the way for the development of highly effective combination immunotherapy strategies that modulate both innate and adaptive antitumour immune responses.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1038/s41568-019-0183-zDOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7002027PMC
October 2019

The GABA receptor GABRR1 is expressed on and functional in hematopoietic stem cells and megakaryocyte progenitors.

Proc Natl Acad Sci U S A 2019 09 26;116(37):18416-18422. Epub 2019 Aug 26.

Institute for Stem Cell Biology and Regenerative Medicine, Stanford University School of Medicine, Stanford, CA 94305;

GABRR1 is a rho subunit receptor of GABA, the major inhibitory neurotransmitter in the mammalian brain. While most investigations of its function focused on the nervous system, its regulatory role in hematopoiesis has not been reported. In this study, we found GABRR1 is mainly expressed on subsets of human and mouse hematopoietic stem cells (HSCs) and megakaryocyte progenitors (MkPs). GABRR1-negative (GR-) HSCs led to higher donor-derived hematopoietic chimerism than GABRR1-positive (GR+) HSCs. GR+ but not GR- HSCs and MkPs respond to GABA in patch clamp studies. Inhibition of GABRR1 via genetic knockout or antagonists inhibited MkP differentiation and reduced platelet numbers in blood. Overexpression of GABRR1 or treatment with agonists significantly promoted MkP generation and megakaryocyte colonies. Thus, this study identifies a link between the neural and hematopoietic systems and opens up the possibility of manipulating GABA signaling for platelet-required clinical applications.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1073/pnas.1906251116DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6744911PMC
September 2019

De novo mutations in mitochondrial DNA of iPSCs produce immunogenic neoepitopes in mice and humans.

Nat Biotechnol 2019 10 19;37(10):1137-1144. Epub 2019 Aug 19.

Department of Surgery, Division of Cardiothoracic Surgery, Transplant and Stem Cell Immunobiology Lab, University of California, San Francisco, San Francisco, CA, USA.

The utility of autologous induced pluripotent stem cell (iPSC) therapies for tissue regeneration depends on reliable production of immunologically silent functional iPSC derivatives. However, rejection of autologous iPSC-derived cells has been reported, although the mechanism underlying rejection is largely unknown. We hypothesized that de novo mutations in mitochondrial DNA (mtDNA), which has far less reliable repair mechanisms than chromosomal DNA, might produce neoantigens capable of eliciting immune recognition and rejection. Here we present evidence in mice and humans that nonsynonymous mtDNA mutations can arise and become enriched during reprogramming to the iPSC stage, long-term culture and differentiation into target cells. These mtDNA mutations encode neoantigens that provoke an immune response that is highly specific and dependent on the host major histocompatibility complex genotype. Our results reveal that autologous iPSCs and their derivatives are not inherently immunologically inert for autologous transplantation and suggest that iPSC-derived products should be screened for mtDNA mutations.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1038/s41587-019-0227-7DOI Listing
October 2019
-->