Approximately 10% of peripheral CD4+ cells and less than 1% of CD8+ cells in normal unimmunized adult mice express the IL-2 receptor alpha-chain (CD25) molecules. When CD4+ cell suspensions prepared from BALB/c nu/+ mice lymph nodes and spleens were depleted of CD25+ cells by specific mAb and C, and then inoculated into BALB/c athymic nude (nu/nu) mice, all recipients spontaneously developed histologically and serologically evident autoimmune diseases (such as thyroiditis, gastritis, insulitis, sialoadenitis, adrenalitis, oophoritis, glomerulonephritis, and polyarthritis); some mice also developed graft-vs-host-like wasting disease. Reconstitution of CD4+CD25+ cells within a limited period after transfer of CD4+CD25- cells prevented these autoimmune developments in a dose-dependent fashion, whereas the reconstitution several days later, or inoculation of an equivalent dose of CD8+ cells, was far less efficient for the prevention. When nu/nu mice were transplanted with allogeneic skins or immunized with xenogeneic proteins at the time of CD25- cell inoculation, they showed significantly heightened immune responses to the skins or proteins, and reconstitution of CD4+CD25+ cells normalized the responses. Taken together, these results indicate that CD4+CD25+ cells contribute to maintaining self-tolerance by down-regulating immune response to self and non-self Ags in an Ag-nonspecific manner, presumably at the T cell activation stage; elimination/reduction of CD4+CD25+ cells relieves this general suppression, thereby not only enhancing immune responses to non-self Ags, but also eliciting autoimmune responses to certain self-Ags. Abnormality of this T cell-mediated mechanism of peripheral tolerance can be a possible cause of various autoimmune diseases.

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Immunologic self-tolerance maintained by activated T cells expressing IL-2 receptor alpha-chains (CD25). Breakdown of a single mechanism of self-tolerance causes various autoimmune diseases.

CA : A Cancer Journal for Clinicians

BackgroundMost patients with locally advanced, unresectable, non–small-cell lung cancer (NSCLC) have disease progression despite definitive chemoradiotherapy (chemotherapy plus concurrent radiation therapy). This phase 3 study compared the anti–programmed death ligand 1 antibody durvalumab as consolidation therapy with placebo in patients with stage III NSCLC who did not have disease progression after two or more cycles of platinum-based chemoradiotherapy. MethodsWe randomly assigned patients, in a 2:1 ratio, to receive durvalumab (at a dose of 10 mg per kilogram of body weight intravenously) or placebo every 2 weeks for up to 12 months. The study drug was administered 1 to 42 days after the patients had received chemoradiotherapy. The coprimary end points were progression-free survival (as assessed by means of blinded independent central review) and overall survival (unplanned for the interim analysis). Secondary end points included 12-month and 18-month progression-free survival rates, the objective res...

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Durvalumab after Chemoradiotherapy in Stage III Non–Small-Cell Lung Cancer

PLoS BIOLOGY Senescence-Associated Secretory Phenotypes Reveal Cell-Nonautonomous Functions of Oncogenic RAS and the p53 Tumor Suppressor Jean-Philippe Coppe 1 , Christopher K. Patil 1[ , Francis Rodier 1,2[ , Yu Sun 3 , Denise P. Mun oz 1,2 , Joshua Goldstein 1¤ , Peter S. Nelson 3 , Pierre-Yves Desprez 1,4 , Judith Campisi 1,2* 1 Life Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California, United States of America, 2 Buck Institute for Age Research, Novato, California, United States of America, 3 Division of Human Biology, Fred Hutchinson Cancer Research Center, Seattle, Washington, United States of America, 4 California Pacific Medical Center Research Institute, San Francisco, California, United States of America Cellular senescence suppresses cancer by arresting cell proliferation, essentially permanently, in response to oncogenic stimuli, including genotoxic stress. We modified the use of antibody arrays to provide a quantitative assessment of factors secreted by senescent cells. We show that human cells induced to senesce by genotoxic stress secrete myriad factors associated with inflammation and malignancy. This senescence-associated secretory phenotype (SASP) developed slowly over several days and only after DNA damage of sufficient magnitude to induce senescence. Remarkably similar SASPs developed in normal fibroblasts, normal epithelial cells, and epithelial tumor cells after genotoxic stress in culture, and in epithelial tumor cells in vivo after treatment of prostate cancer patients with DNA- damaging chemotherapy. In cultured premalignant epithelial cells, SASPs induced an epithelial–mesenchyme transition and invasiveness, hallmarks of malignancy, by a paracrine mechanism that depended largely on the SASP factors interleukin (IL)-6 and IL-8. Strikingly, two manipulations markedly amplified, and accelerated development of, the SASPs: oncogenic RAS expression, which causes genotoxic stress and senescence in normal cells, and functional loss of the p53 tumor suppressor protein. Both loss of p53 and gain of oncogenic RAS also exacerbated the promalignant paracrine activities of the SASPs. Our findings define a central feature of genotoxic stress-induced senescence. Moreover, they suggest a cell-nonautonomous mechanism by which p53 can restrain, and oncogenic RAS can promote, the development of age-related cancer by altering the tissue microenvironment. Citation: Coppe JP, Patil CK, Rodier F, Sun Y, Mun oz DP, et al. (2008) Senescence-associated secretory phenotypes reveal cell-nonautonomous functions of oncogenic RAS and the p53 tumor suppressor. PLoS Biol 6(12): e301. doi:10.1371/journal.pbio.0060301 Introduction Cancer is a multistep disease in which cells acquire increasingly malignant phenotypes. These phenotypes are acquired in part by somatic mutations, which derange normal controls over cell proliferation (growth), survival, invasion, and other processes important for malignant tumorigenesis [1]. In addition, there is increasing evidence that the tissue microenvironment is an important determinant of whether and how malignancies develop [2,3]. Normal tissue environ- ments tend to suppress malignant phenotypes, whereas abnormal tissue environments such at those caused by inﬂammation can promote cancer progression. Cancer development is restrained by a variety of tumor suppressor genes. Some of these genes permanently arrest the growth of cells at risk for neoplastic transformation, a process termed cellular senescence [4–6]. Two tumor suppressor pathways, controlled by the p53 and p16INK4a/pRB proteins, regulate senescence responses. Both pathways integrate multiple aspects of cellular physiology and direct cell fate towards survival, death, proliferation, or growth arrest, depending on the context [7,8]. Several lines of evidence indicate that cellular senescence is a potent tumor-suppressive mechanism [4,9,10]. Many poten- tially oncogenic stimuli (e.g., dysfunctional telomeres, DNA PLoS Biology | www.plosbiology.org damage, and certain oncogenes) induce senescence [6,11]. Moreover, mutations that dampen the p53 or p16INK4a/pRB pathways confer resistance to senescence and greatly increase cancer risk [12,13]. Most cancers harbor mutations in one or both of these pathways [14,15]. Lastly, in mice and humans, a senescence response to strong mitogenic signals, such as those delivered by certain oncogenes, prevents premalignant lesions from progressing to malignant cancers [16–19]. Academic Editor: Julian Downward, Cancer Research UK, United Kingdom Received June 27, 2008; Accepted October 22, 2008; Published December 2, 2008 Copyright: O 2008 Coppe et al. This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited. Abbreviations: CM, conditioned medium; DDR, DNA damage response; ELISA, enzyme-linked immunosorbent assay; EMT, epithelial–mesenchymal transition; GSE, genetic suppressor element; IL, interleukin; MIT, mitoxantrone; PRE, presenescent; PrEC, normal human prostate epithelial cell; REP, replicative exhaustion; SASP, senescence-associated secretory phenotype; SEN, senescent; shRNA, short hairpin RNA; XRA, X-irradiation * To whom correspondence should be addressed. E-mail: jcampisi@lbl.gov [ These authors contributed equally to this work. ¤ Current address: Genomics Institute of the Novartis Research Foundation, San Diego, California, United States of America December 2008 | Volume 6 | Issue 12 | e301

Senescence-Associated Secretory Phenotypes Reveal Cell-Nonautonomous Functions of Oncogenic RAS and the p53 Tumor Suppressor

EVOLUTION: Of Mice . . .


 A master immunoregulator FoxP3-expressing CD4+ Treg cellsplay an ameliorative role in the severity of MS/EAE disease. However, it is contradictory that the aged T cell immune system possesses relatively enhanced thymic CD4+ Treg generation and accumulated peripheral CD4+ Treg cells, but coupled with severe MS/EAE symptoms and pathology. Using single-cell (sc)-RNA-Seq assay, we found that CNS-infiltrating CD4+ Treg cells in aged EAE mouse model had increased pathogenic properties, showing co-expression of infg and il17a with foxp3, and reduced suppressive effect, exhibiting increased clonal expansion of pathogenic CD4+ T cells. These indicate changed Treg quality in aged EAE mice. Transient inhibition of aged peripheral FoxP3+ Treg cells mitigated the disease severity in the aged mice. The ameliorative effect was more significant when partially inhibiting FoxP3+ Treg cells with a drug P300i than completely depleting FoxP3+ Treg cells in FoxP3DTR transgenic mice. The mitigation is probably attributed to the correction of Treg cell distribution outside and inside the CNS. By inhibiting accumulated FoxP3+ Treg cells adhering to the brain’s choroid plexus (outside the CNS), the IFN-g-producing cells can be restored, thereby, the impediment of immune cell trafficking into the inflamed CNS is released in aged EAE mice. As a result, the proportion of myelin-specific CD4+ Treg cells inside the CNS was increased for repairing neuroinflammatory damage. Together, the underlying mechanism of severe MS symptoms in elderly patients is associated with the accumulation of Treg cells outside the CNS, which prevents the reparative antigen-specific Treg cells from entering the CNS during the disease.
 Supported by NIH/NIAID R01AI121147

Aging impairs regulatory T cell (Treg) cells to affect late-onset (aged) multiple sclerosis (MS) – with the model of experimental autoimmune encephalomyelitis (EAE)

9777 AGING The driving force behind age-related neuroinflammatory disorders is primarily associated with the aberrant aged immune system, particularly T cellassociated cellular immunity. The T cells participating in such disorders include pathogenic T effector (Teff) and protective regulatory T (Treg) cells. Generally, FoxP3CD4 Treg cells play an ameliorative role in age-related neuroinflammatory disorders’ onset and severity [1]. However, there are distinct functions (suppressing inflammation or inhibiting immunity) performed by these Treg cells, depending on their locality, such as residing in peripheral lymphoid organs or in certain tissues (termed tissue-resident Treg) [2]. The CNS is considered immune privileged, and generally it is isolated from the lymphatic system by specialized membranes, including the blood-brain barrier (BBB) and choroid plexus (CP). This may result in different proportions of T cell distribution inside and outside of the CNS. Recently work found that distributions of young and aged polyclonal/panTreg cells in the peripheral lymphoid organs, termed pTreg, and the central nervous system (CNS), termed CNS-Treg, during the autoimmune neuroinflammation were different. The percentages of pTreg cells were lower in the inflamed aged CNS, but higher in the aged peripheral lymphoid organs, compared to young conterparts [3].

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Are aged pTreg cells “the more the better”?

Age-associated systemic, chronic, sterile inflammatory condition (inflammaging) is partially attributed to increased self (auto)-reactivity, resulting from disruption of central tolerance in the aged, involuted thymus. Age-related thymic involution causally results from gradually declined expression of the transcription factor forkhead box N1 (FOXN1) in thymic epithelial cells (TECs), while exogenous FOXN1 in TECs can significantly rescue age-related thymic involution. Given the findings that induced TECs (iTECs) from FOXN1-overexpressing embryonic fibroblasts can generate an ectopic de novo thymus under the kidney capsule and intra-thymically injected natural young TECs can lead to middle-aged thymus regrowth, we sought to expand upon these two findings by applying them as a novel thymic rejuvenation strategy with two types of promoter-driven (Rosa26CreERT and FoxN1Cre) Cre-mediated iTECs. We engrafted iTECs, rather than natural young TECs, directly into the aged thymus and/or peri-thymus and found a significantly rejuvenated architecture and function in the native aged murine thymus. The engrafted iTECs drove regrowth of the aged thymus in both male and female mice, showing not only increased thymopoiesis, but also reinforcement of thymocyte negative selection, thereby, reducing senescent T cells and auto-reactive T cell-mediated inflammaging phenotypes in old mice. Therefore, this is a promising thymic rejuvenation strategy with preclinical significance, which can potentially rescue declined thymopoiesis and impaired negative selection to significantly, albeit partially, restore the defective central tolerance and reduce subclinical chronic inflammatory symptoms in the elderly. Graphical Abstract O_FIG O_LINKSMALLFIG WIDTH=165 HEIGHT=200 SRC="FIGDIR/small/995357v1_ufig1.gif" ALT="Figure 1"> View larger version (39K): org.highwire.dtl.DTLVardef@7f8cfborg.highwire.dtl.DTLVardef@d1c4org.highwire.dtl.DTLVardef@1cbc905org.highwire.dtl.DTLVardef@1fa9e8d_HPS_FORMAT_FIGEXP M_FIG C_FIG A novel rejuvenation strategy via the FOXN1-TEC axis using induced two types of FOXN1-overexpressing embryonic fibroblasts (termed iTECs) by intrathymic injection is able to counteract age-related thymic involution, which rescued negative selection, thereby, reducing peripheral T cell-associated inflammaging conditions.

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Dong-Ming Su

Papers

Aging impairs regulatory T cell (Treg) cells to affect late-onset (aged) multiple sclerosis (MS) – with the model of experimental autoimmune encephalomyelitis (EAE)

Are aged pTreg cells “the more the better”?

Thymic rejuvenation via induced thymic epithelial cells (iTECs) from FOXN1-overexpressing fibroblasts to counteract inflammaging