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Gund R, Christiano AM. Impaired autophagy promotes hair loss in the C3H/HeJ mouse model of alopecia areata. Autophagy 2023; 19:296-305. [PMID: 35652954 PMCID: PMC9809940 DOI: 10.1080/15548627.2022.2074104] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2021] [Revised: 04/26/2022] [Accepted: 04/29/2022] [Indexed: 01/07/2023] Open
Abstract
Alopecia areata (AA) involves an aberrant immune attack on the hair follicle (HF), which leads to hair loss. Previous genetic data from our lab pointed to a connection between macroautophagy/autophagy and AA pathogenesis, and GWAS identified STX17, CLEC16A and BCL2L11/BIM as risk factors for AA. Additionally, AA patients have copy number deletions in region spanning the ATG4B gene. To test whether autophagy might contribute to disease pathogenesis in AA, we investigated autophagic activity in C3H/HeJ mouse model. We found that autophagy protein SQSTM1 accumulated in HF of AA mice, while in immune cells from AA skin-draining lymph nodes SQSTM1 was not altered, suggesting that autophagic activity is inhibited in the HF of AA mice. Induction of autophagy with Tat-BECN1 peptide attenuated AA, while treatment with the autophagy blocker chloroquine promoted disease, compared to untreated AA mice. Together, our findings suggest the involvement of impaired autophagy in disease pathogenesis of AA.Abbreviations: AA: alopecia areata; CQ: chloroquine; GWAS: genome-wide association studies; HF: hair follicle; MHC: major histocompatibility complex; SDLN: skin-draining lymph nodes.
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Affiliation(s)
- Rupali Gund
- Department of Dermatology, Vagelos College of Physicians and Surgeons, Columbia University, New York, New YorkUSA
| | - Angela M. Christiano
- Department of Dermatology, Vagelos College of Physicians and Surgeons, Columbia University, New York, New YorkUSA
- Department of Genetics and Development, Vagelos College of Physicians and Surgeons, Columbia University, New York, NY, USA
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2
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Gund R, Mace E, Christiano A. 139 Pathogenic CD8+ T cell infiltration and immune synapse formation in alopecia areata hair follicles. J Invest Dermatol 2022. [DOI: 10.1016/j.jid.2022.05.145] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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3
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Gund R, Mace E, Christiano A. 100 Pathogenic CD8+ T cells form cytolytic immune synapses to mediate hair follicle destruction in Alopecia Areata. J Invest Dermatol 2021. [DOI: 10.1016/j.jid.2021.02.118] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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4
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Erjavec S, Abdelaziz A, Wang C, Lin P, Monga I, Gund R, Ionita-Laza I, Petukhova L, Christiano A. 182 Functional genomic analysis of STX17 in alopecia areata reveals a novel role in melanocyte function. J Invest Dermatol 2021. [DOI: 10.1016/j.jid.2021.02.202] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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5
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Gund R, Zirmire R, J H, Kansagara G, Jamora C. Histological and Immunohistochemical Examination of Stem Cell Proliferation and Reepithelialization in the Wounded Skin. Bio Protoc 2021; 11:e3894. [PMID: 33732783 DOI: 10.21769/bioprotoc.3894] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2020] [Accepted: 12/14/2020] [Indexed: 11/02/2022] Open
Abstract
The skin is the largest organ that protects our body from the external environment and it is constantly exposed to pathogenic insults and injury. Repair of damage to this organ is carried out by a complex process involving three overlapping phases of inflammation, proliferation and remodeling. Histological analysis of wounded skin is a convenient approach to examine broad alterations in tissue architecture and investigate cells in their indigenous microenvironment. In this article we present a protocol for immunohistochemical examination of wounded skin to study mechanisms involved in regulating stem cell activity, which is a vital component in the repair of the damaged tissue. Performing such histological analysis enables the understanding of the spatial relationship between cells that interact in the specialized wound microenvironment. The analytical tools described herein permit the quantitative measurement of the regenerative ability of stem cells adjacent to the wound and the extent of re-epithelialization during wound closure. These protocols can be adapted to investigate numerous cellular processes and cell types within the wounded skin.
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Affiliation(s)
- Rupali Gund
- Department of Dermatology, Columbia University, New York, USA
| | - Ravindra Zirmire
- IFOM-inStem Joint Research Laboratory, Centre for Inflammation and Tissue Homeostasis, Institute for Stem Cell Science and Regenerative Medicine (inStem), Bangalore, Karnataka, India.,Shanmugha Arts, Science, Technology and Research Academy (SASTRA) University, Thanjavur, Tamil Nadu, India
| | - Haarshaadri J
- IFOM-inStem Joint Research Laboratory, Centre for Inflammation and Tissue Homeostasis, Institute for Stem Cell Science and Regenerative Medicine (inStem), Bangalore, Karnataka, India
| | - Gaurav Kansagara
- IFOM-inStem Joint Research Laboratory, Centre for Inflammation and Tissue Homeostasis, Institute for Stem Cell Science and Regenerative Medicine (inStem), Bangalore, Karnataka, India.,Manipal Academy of Higher Education (MAHE), Manipal, Karnataka, India
| | - Colin Jamora
- IFOM-inStem Joint Research Laboratory, Centre for Inflammation and Tissue Homeostasis, Institute for Stem Cell Science and Regenerative Medicine (inStem), Bangalore, Karnataka, India
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6
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Gund R, Erjavec S, Christiano A. 427 Blockade of autophagy accelerates the development of alopecia areata. J Invest Dermatol 2019. [DOI: 10.1016/j.jid.2019.03.503] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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7
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Balyan R, Gund R, Chawla AS, Khare SP, Pradhan SJ, Rane S, Galande S, Durdik JM, George A, Bal V, Rath S. Correlation of cell-surface CD8 levels with function, phenotype and transcriptome of naive CD8 T cells. Immunology 2018; 156:384-401. [PMID: 30556901 DOI: 10.1111/imm.13036] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2018] [Revised: 11/20/2018] [Accepted: 11/21/2018] [Indexed: 11/27/2022] Open
Abstract
We have previously demonstrated co-receptor level-associated functional heterogeneity in apparently homogeneous naive peripheral CD4 T cells, dependent on MHC-mediated tonic signals. Maturation pathways can differ between naive CD4 and naive CD8 cells, so we tested whether the latter showed similar co-receptor level-associated functional heterogeneity. We report that, when either polyclonal and T-cell receptor (TCR)-transgenic monoclonal peripheral naive CD8 T cells from young mice were separated into CD8hi and CD8lo subsets, CD8lo cells responded poorly, but CD8hi and CD8lo subsets of CD8 single-positive (SP) thymocytes responded similarly. CD8lo naive CD8 T cells were smaller and showed lower levels of some cell-surface molecules, but higher levels of the negative regulator CD5. In addition to the expected peripheral decline in CD8 levels on transferred naive CD8 T cells in wild-type (WT) but not in MHC class I-deficient recipient mice, short-duration naive T-cell-dendritic cell (DC) co-cultures in vitro also caused co-receptor down-modulation in CD8 T cells but not in CD4 T cells. Constitutive pZAP70/pSyk and pERK levels ex vivo were lower in CD8lo naive CD8 T cells and dual-specific phosphatase inhibition partially rescued their hypo-responsiveness. Bulk mRNA sequencing showed major differences in the transcriptional landscapes of CD8hi and CD8lo naive CD8 T cells. CD8hi naive CD8 T cells showed enrichment of genes involved in positive regulation of cell cycle and survival. Our data show that naive CD8 T cells show major differences in their signaling, transcriptional and functional landscapes associated with subtly altered CD8 levels, consistent with the possibility of peripheral cellular aging.
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Affiliation(s)
- Renu Balyan
- National Institute of Immunology, New Delhi, India.,Yong Loo Lin School of Medicine, National University of Singapore, Singapore city, Singapore
| | - Rupali Gund
- National Institute of Immunology, New Delhi, India
| | | | - Satyajeet P Khare
- Indian Institute of Science Education and Research, Pune, India.,Symbiosis School of Biological Sciences, Pune, India
| | | | - Sanket Rane
- National Institute of Immunology, New Delhi, India
| | - Sanjeev Galande
- Indian Institute of Science Education and Research, Pune, India
| | | | - Anna George
- National Institute of Immunology, New Delhi, India
| | - Vineeta Bal
- National Institute of Immunology, New Delhi, India.,Indian Institute of Science Education and Research, Pune, India
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Gund R, Lee P, Dutta A, Pincha N, Rana I, Ghosh S, Witherden D, Kandyba E, MacLeod A, Kobielak K, Havran W, Jamora C. 1349 Stimulation of hair follicle stem cell proliferation through an IL-1α dependent activation of γδT-cells. J Invest Dermatol 2018. [DOI: 10.1016/j.jid.2018.03.1366] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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9
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Lee P, Gund R, Dutta A, Pincha N, Rana I, Ghosh S, Witherden D, Kandyba E, MacLeod A, Kobielak K, Havran WL, Jamora C. Stimulation of hair follicle stem cell proliferation through an IL-1 dependent activation of γδT-cells. eLife 2017; 6. [PMID: 29199946 PMCID: PMC5714500 DOI: 10.7554/elife.28875] [Citation(s) in RCA: 39] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2017] [Accepted: 11/09/2017] [Indexed: 02/01/2023] Open
Abstract
The cutaneous wound-healing program is a product of a complex interplay among diverse cell types within the skin. One fundamental process that is mediated by these reciprocal interactions is the mobilization of local stem cell pools to promote tissue regeneration and repair. Using the ablation of epidermal caspase-8 as a model of wound healing in Mus musculus, we analyzed the signaling components responsible for epithelial stem cell proliferation. We found that IL-1α and IL-7 secreted from keratinocytes work in tandem to expand the activated population of resident epidermal γδT-cells. A downstream effect of activated γδT-cells is the preferential proliferation of hair follicle stem cells. By contrast, IL-1α-dependent stimulation of dermal fibroblasts optimally stimulates epidermal stem cell proliferation. These findings provide new mechanistic insights into the regulation and function of epidermal cell–immune cell interactions and into how components that are classically associated with inflammation can differentially influence distinct stem cell niches within a tissue. The skin is a physical barrier that protects the body from the outside world. If the skin is injured, the body mounts a “wound healing” response to rapidly mend and restore this protective barrier. Wound healing is a complex process and relies on the different types of cells in the skin communicating with each other. Stem cells provide tissues, like the skin, with new cells. Normally, stem cells are in a resting or inactive state. Yet, during wound healing, stem cells near the injured area are awakened and start producing more cells to repair the wound. Understanding how stem cells become activated in a wound has proved challenging because only a small number of cells near a damaged site will respond, and it is difficult to distinguish their response from that of other cells slightly further away. Now, Lee et al. overcome this hurdle by analyzing a genetically engineered mouse in which the entire skin displays a wound healing response, even without any injury or trauma. In these mice, most of the stem cells in the skin are awakened from their normal resting state and behave as if there is a wound to heal. It turns out that a protein called interleukin-1, which is released from damaged skin cells known as keratinocytes, can activate two different groups of stem cells in the skin to help repair the injured tissue. One group lives in the hair follicle and is normally responsible for replacing the hair that falls from the body. Lee et al. found that when the skin is wounded interleukin-1 activates certain immune cells (called γδT-cells). These immune cells then awaken the resting stem cells in the hair follicle to multiply and travel to the wound site to repair the injury. The other group of stem cells resides in the outermost layer of the skin. Interleukin-1 can also activate so-called fibroblast cells, which then stimulate this second group of stem cells to divide and cover the open wound. Quickly healing wounds has many health benefits such as preventing infection and shortening the time to recover from an injury. These new findings may help to repair injured skin in diseases such as diabetes, where wounds can take months to heal and often leads to permanent tissue damage. The next challenge is to identify the cues that instruct the stem cells to travel to the wound site and turn into the specific cells that are required to replace the damaged cells.
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Affiliation(s)
- Pedro Lee
- Section of Cell and Developmental Biology, University of California, San Diego, La Jolla, United States
| | - Rupali Gund
- IFOM-inStem Joint Research Laboratory, Centre for Inflammation and Tissue Homeostasis, Institute for Stem Cell Biology and Regenerative Medicine, Bangalore, India
| | - Abhik Dutta
- IFOM-inStem Joint Research Laboratory, Centre for Inflammation and Tissue Homeostasis, Institute for Stem Cell Biology and Regenerative Medicine, Bangalore, India
| | - Neha Pincha
- IFOM-inStem Joint Research Laboratory, Centre for Inflammation and Tissue Homeostasis, Institute for Stem Cell Biology and Regenerative Medicine, Bangalore, India.,Graduate Studies, Manipal University, Manipal, India
| | - Isha Rana
- IFOM-inStem Joint Research Laboratory, Centre for Inflammation and Tissue Homeostasis, Institute for Stem Cell Biology and Regenerative Medicine, Bangalore, India.,Shanmugha Arts, Science, Technology and Research Academy (SASTRA) University, Thanjavur, India
| | - Subhasri Ghosh
- IFOM-inStem Joint Research Laboratory, Centre for Inflammation and Tissue Homeostasis, Institute for Stem Cell Biology and Regenerative Medicine, Bangalore, India
| | - Deborah Witherden
- Department of Immunology and Microbial Science, The Scripps Research Institute, La Jolla, United States
| | - Eve Kandyba
- Eli and Edythe Broad Center for Regenerative Medicine & Stem Cell Research, Department of Pathology, University of Southern California, Los Angeles, United States
| | - Amanda MacLeod
- Department of Immunology and Microbial Science, The Scripps Research Institute, La Jolla, United States
| | - Krzysztof Kobielak
- Eli and Edythe Broad Center for Regenerative Medicine & Stem Cell Research, Department of Pathology, University of Southern California, Los Angeles, United States
| | - Wendy L Havran
- Department of Immunology and Microbial Science, The Scripps Research Institute, La Jolla, United States
| | - Colin Jamora
- IFOM-inStem Joint Research Laboratory, Centre for Inflammation and Tissue Homeostasis, Institute for Stem Cell Biology and Regenerative Medicine, Bangalore, India
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10
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Balyan R, Gund R, Ebenezer C, Khalsa JK, Verghese DA, Krishnamurthy T, George A, Bal V, Rath S, Chaudhry A. Modulation of Naive CD8 T Cell Response Features by Ligand Density, Affinity, and Continued Signaling via Internalized TCRs. J Immunol 2017; 198:1823-1837. [PMID: 28100678 DOI: 10.4049/jimmunol.1600083] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/14/2016] [Accepted: 12/20/2016] [Indexed: 01/08/2023]
Abstract
T cell response magnitudes increase with increasing antigenic dosage. However, it is unclear whether ligand density only modulates the proportions of responding ligand-specific T cells or also alters responses at the single cell level. Using brief (3 h) exposure of TCR-transgenic mouse CD8 T cells in vitro to varying densities of cognate peptide-MHC ligand followed by ligand-free culture in IL-2, we found that ligand density determined the frequencies of responding cells but not the expression levels of the early activation marker molecule, CD69. Cells with low glucose uptake capacity and low protein synthesis rates were less ligand-sensitive, implicating metabolic competence in the response heterogeneity of CD8 T cell populations. Although most responding cells proliferated, ligand density was associated with time of entry into proliferation and with the extent of cell surface TCR downmodulation. TCR internalization was associated, regardless of the ligand density, with rapidity of c-myc induction, loss of the cell cycle inhibitor p27kip1, metabolic reprogramming, and cell cycle entry. A low affinity peptide ligand behaved, regardless of ligand density, like a low density, high affinity ligand in all these parameters. Inhibition of signaling after ligand exposure selectively delayed proliferation in cells with internalized TCRs. Finally, internalized TCRs continued to signal and genetic modification of TCR internalization and trafficking altered the duration of signaling in a T cell hybridoma. Together, our findings indicate that heterogeneity among responding CD8 T cell populations in their ability to respond to TCR-mediated stimulation and internalize TCRs mediates detection of ligand density or affinity, contributing to graded response magnitudes.
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Affiliation(s)
- Renu Balyan
- National Institute of Immunology, New Delhi 110067, India; and
| | - Rupali Gund
- National Institute of Immunology, New Delhi 110067, India; and
| | - Chitra Ebenezer
- National Institute of Immunology, New Delhi 110067, India; and
| | | | | | | | - Anna George
- National Institute of Immunology, New Delhi 110067, India; and
| | - Vineeta Bal
- National Institute of Immunology, New Delhi 110067, India; and
| | - Satyajit Rath
- National Institute of Immunology, New Delhi 110067, India; and
| | - Ashutosh Chaudhry
- National Institute of Immunology, New Delhi 110067, India; and.,Memorial Sloan Kettering Cancer Center, New York, NY 10065
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Rath S, Rane S, Das R, Gund R, Balyan R, Das A, Khalsa J, Ranganathan V, Prabhu S, Mattoo H, Durdik J, George A, Bal V. A role for MHC-mediated signalling in the functional and phenotypic heterogeneity of naive T cells (IRC8P.454). The Journal of Immunology 2015. [DOI: 10.4049/jimmunol.194.supp.129.18] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
Abstract
Variability in cellular activation in the immune system can have diverse consequences, resulting in heterogeneity in effector programming and function as well as in cell survival. While examining relationships between lymphocyte heterogeneity and functionality, we find that apparently unimodally distributed coreceptor heterogeneity among naive T cells, simplistically expected to be due to intrinsic noise, is not only correlated with major functional variation but is modulated by extrinsic microenvironmental cues in vivo. Thus, when naive T cells from young mice are separated into coreceptor-hi and coreceptor-lo subsets, we find that coreceptor-lo cells are smaller, have higher CD5 levels, respond poorly, are more susceptible to death, and show altered effector differentiation. Human coreceptor-lo and coreceptor-hi naive T cells show similar differences. Coreceptor-lo and coreceptor-hi subsets of 'single-positive' (SP) thymocytes do not show these differences, whereas peripheral coreceptor-lo and coreceptor-hi subsets of naive T cells from TCR-transgenic mice do. Adoptive transfer-mediated parking in vivo in MHC-sufficient but not in MHC-deficient mice causes reduction in coreceptor levels, increase in CD5 levels and hyporesponsiveness in naive T cells. Naive T cells from aged mice show similar phenotypic and functional differences. Thus, our data show complex roles for tonic signaling in the functional heterogeneity of naive T cell populations.
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Affiliation(s)
| | - Sanket Rane
- 1National Institute of Immunology, New Delhi, India
| | | | - Rupali Gund
- 1National Institute of Immunology, New Delhi, India
| | - Renu Balyan
- 1National Institute of Immunology, New Delhi, India
| | | | | | | | - Savit Prabhu
- 1National Institute of Immunology, New Delhi, India
| | - Hamid Mattoo
- 1National Institute of Immunology, New Delhi, India
| | | | - Anna George
- 1National Institute of Immunology, New Delhi, India
| | - Vineeta Bal
- 1National Institute of Immunology, New Delhi, India
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12
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Salam N, Rane S, Das R, Faulkner M, Gund R, Kandpal U, Lewis V, Mattoo H, Prabhu S, Ranganathan V, Durdik J, George A, Rath S, Bal V. T cell ageing: effects of age on development, survival & function. Indian J Med Res 2013; 138:595-608. [PMID: 24434315 PMCID: PMC3928693] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Age associated decline of the immune system continues to be a major health concern. All components of innate and adaptive immunity are adversely affected to lesser or greater extent by ageing resulting in an overall decline of immunocompetence. As a result in the aged population, there is increased susceptibility to infection, poor responses to vaccination, and increased incidence of autoreactivity. There is an increasing focus on the role of T cells during ageing because of their impact on the overall immune responses. A steady decline in the production of fresh naïve T cells, more restricted T cell receptor (TCR) repertoire and weak activation of T cells are some of the effects of ageing. In this review we summarize our present understanding of the effects of ageing on naïve CD4 T cells and potential approaches for therapeutic interventions to restore protective immunity in the aged population.
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Affiliation(s)
- Nasir Salam
- National Institute of Immunology, New Delhi, India,Reprint requests: Dr Nasir Salam / Dr Vineeta Bal, National Institute of Immunology, Aruna Asaf Ali Road, New Delhi 110 067, India e-mail: and
| | - Sanket Rane
- National Institute of Immunology, New Delhi, India
| | | | - Matthew Faulkner
- Department of Biological Sciences, University of Arkansas, Fayetteville, Arkansas, USA
| | - Rupali Gund
- National Institute of Immunology, New Delhi, India
| | - Usha Kandpal
- National Institute of Immunology, New Delhi, India
| | - Virginia Lewis
- Department of Biological Sciences, University of Arkansas, Fayetteville, Arkansas, USA
| | - Hamid Mattoo
- National Institute of Immunology, New Delhi, India
| | - Savit Prabhu
- National Institute of Immunology, New Delhi, India
| | | | - Jeannine Durdik
- Department of Biological Sciences, University of Arkansas, Fayetteville, Arkansas, USA
| | - Anna George
- National Institute of Immunology, New Delhi, India
| | | | - Vineeta Bal
- National Institute of Immunology, New Delhi, India,Reprint requests: Dr Nasir Salam / Dr Vineeta Bal, National Institute of Immunology, Aruna Asaf Ali Road, New Delhi 110 067, India e-mail: and
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Gund R, Ebenezer C, Thyagarajan K, Chaudhry A, George A, Bal V, Rath S. Antigenic ligand density modulates execution of naïve CD8+ T cell response programme (110.1). The Journal of Immunology 2012. [DOI: 10.4049/jimmunol.188.supp.110.1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
Abstract
Upon brief exposure to antigenic stimulation, naïve CD8+ T lymphocytes execute an autonomous programme of several rounds of proliferation and maturation into effector cytotoxic cells. We have studied the role of ligand density as a modifier of this program using T cell receptor (TCR)-transgenic CD8+ T cell activation by short-duration stimulation in vitro. Over the entire ligand density range studied, we observe a graded increase in the frequency of responder naïve T cells that upregulate the expression of CD69, an early activation marker. However, the levels of induced CD69 are similar at all ligand densities. When CD69+ T cells are purified at early stages and cultured, most undergo successive proliferation cycles, showing that the execution of the autonomous programme during CD8+ T cell response is independent of ligand density. However, at very low ligand densities, the efficiency with which CD69+ T cells enter proliferation is poor and slow, leading to lower cell yields. At these ligand densities, post-activation TCR internalization is also inefficient. At any given ligand density, if activated CD69+ T cells that have internalised TCR are separated from those that have not internalised TCR, TCR-high cells show a lag in proliferation regardless of the ligand density. Together, these data indicate that ligand density quantitatively modulates the lag phase of the autonomous proliferation-differentiation programme of CD8+ T cells via TCR internalization-dependent mechanism.
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Affiliation(s)
- Rupali Gund
- 1Immunobiology Laboratory, National Institute of Immunology, New delhi, India
| | - Chitra Ebenezer
- 1Immunobiology Laboratory, National Institute of Immunology, New delhi, India
| | | | - Ashutosh Chaudhry
- 1Immunobiology Laboratory, National Institute of Immunology, New delhi, India
| | - Anna George
- 1Immunobiology Laboratory, National Institute of Immunology, New delhi, India
| | - Vineeta Bal
- 1Immunobiology Laboratory, National Institute of Immunology, New delhi, India
| | - Satyajit Rath
- 1Immunobiology Laboratory, National Institute of Immunology, New delhi, India
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Khare A, Viswanathan B, Gund R, Jain N, Ravindran B, George A, Rath S, Bal V. Role of Bruton’s tyrosine kinase in macrophage apoptosis. Apoptosis 2010; 16:334-46. [DOI: 10.1007/s10495-010-0569-6] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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