Molecular Aspects of Aging: Understanding Lung Aging

Molecular Aspects of Aging: Understanding Lung Aging covers recent research in the mechanisms that contribute to cellular senescence. Covering universal themes in aging, such as the exhaustion of stem cells and subsequent loss of the regenerative refueling of organs as well as immunosenescence, this text illuminates new directions for research not yet explored in the still poorly investigated area of molecular mechanisms of lung aging. The molecular nature of general aging processes is explored with targeted coverage on how to analyze lung aging through experimental approaches.

Table of Contents:
Contributors xi Preface xiii 1 The Demography of Aging 1 David E. Bloom and Sinead Shannon 1.1 Introduction 1 1.2 Demographic trends 1 1.2.1 Fertility rates 2 1.2.2 Mortality rates and life expectancy 2 1.2.3 Proportion of older people 3 1.3 Impact of aging 4 1.3.1 Noncommunicable disease trends 4 1.3.2 Risk factors 5 1.3.3 Impact of NCDs on health and disability 6 1.3.4 Increase in multimorbidities 7 1.3.5 Impact on expenditure 7 1.4 Policy responses 8 1.4.1 Preventing and managing NCDs 8 1.4.2 Promoting exercise 9 1.4.3 Monitoring health-risk behaviors (and chronic health conditions) 9 1.5 Conclusion 9 References 10 2 The Omics of Aging: Insights from Genomes upon Stress 13 Ismene Karakasilioti, Anna Ioannidou, and George A. Garinis 2.1 Introduction 13 2.2 Safeguarding the nuclear genome 14 2.3 NER progerias and their connection to lifespan regulatory mechanisms 15 2.4 Triggering a survival response in the absence of a DNA repair defect 16 2.5 The omics connection between progeria and longevity 19 2.6 Triggering of systemic versus cell-autonomous features of the survival response 20 2.7 The omics connection between NER progeria, transcription, and longevity 21 2.8 Future perspectives 22 References 22 3 Protein Quality Control Coming of Age 27 Silke Meiners 3.1 Introduction 27 3.2 The aging molecular chaperone network 29 3.3 Protein degradation pathways in aging 30 3.3.1 Lysosomal autophagy pathway 30 3.3.2 Ubiquitin–proteasome system 32 3.4 Compartment-specific protein quality control 34 3.4.1 The aging ER stress response 34 3.5 Conclusion 35 References 35 4 Telomerase Function in Aging 41 Rodrigo T. Calado 4.1 Telomeres 41 4.2 Telomerase 43 4.3 Telomeres and human disease 45 4.3.1 Telomere dysfunction in the lungs 46 4.4 Telomeres biology, aging, and longevity 47 4.5 Conclusion 48 References 48 5 The Cellular Senescence Program 53 Pooja Shivshankar and Claude Jourdan Le Saux 5.1 Cellular senescence and evidence of senescence in a cell 53 5.1.1 Characteristics of senescent cells and the inflammatory microenvironment 53 5.1.2 Detection of senescent cells in vitro and in vivo 54 5.2 Conditions associated with cellular senescence 55 5.2.1 Oxidative stress 55 5.2.2 DNA damage 55 5.2.3 Cell cycle arrest and senescence 56 5.3 Mechanisms/pathways of senescence induction 56 5.3.1 The p53/p21 pathway 56 5.3.2 The p16/pRB pathway 57 5.3.3 Convergence/coactivation of p53/p21 and p16/pRB pathways 57 5.3.4 Induction of senescence via molecular signaling 57 5.4 Cellular senescence in aging and age-related diseases of the lungs 58 5.4.1 Normal aging 59 5.4.2 Pneumonia 59 5.4.3 Chronic obstructive pulmonary disease 60 5.4.4 Idiopathic pulmonary fibrosis 60 5.5 Conclusion 61 References 61 6 Signaling Networks Controlling Cellular Senescence 67 Leena P. Desai, Yan Y. Sanders, and Victor J. Thannickal 6.1 Introduction 67 6.2 Classification of cellular senescence 69 6.2.1 Intrinsic pathway 69 6.2.2 Extrinsic pathway 69 6.2.3 Reversibility of cellular senescence 70 6.3 Cross talk of signaling pathways 70 6.3.1 Protein kinases 70 6.3.2 Metabolic pathways 71 6.3.3 Mitochondria and reactive oxygen species 71 6.3.4 Integrin and focal adhesion signaling 72 6.3.5 Transforming growth factor-β1 73 6.3.6 Epigenetic mechanisms 73 6.4 Conclusion 76 References 77 7 Immune Senescence 85 Kevin P. High 7.1 Introduction 85 7.2 Barrier defenses and innate immunity in older adults 86 7.2.1 Barrier defenses 86 7.2.2 Innate immunity 86 7.3 Adaptive immune responses 88 7.3.1 B cell number and function 88 7.3.2 T cell number, subtypes, and function 89 7.3.3 T cell activation, differentiation, exhaustion, and senescence 90 7.4 Consequences of immune senescence 91 7.4.1 Impaired vaccine responses, increased risk of infection, and age-related illness 91 7.4.2 Immune senescence: A cause of aging itself 93 7.5 Conclusion 94 References 95 8 Developmental and Physiological Aging of the Lung 99 Kent E. Pinkerton, Lei Wang, Suzette M. Smiley-Jewell, Jingyi Xu, and Francis H.Y. Green 8.1 Introduction 99 8.2 The aging lung 99 8.2.1 Alterations in lung function and anatomy 99 8.2.2 Oxidative stress and lung antioxidant defenses 101 8.2.3 Immune system changes with aging 101 8.2.4 Body mass 102 8.2.5 Airway receptor and endocrine changes with aging 103 8.3 An animal model of the aging lung: The rat 104 8.3.1 The tracheobronchial tree and epithelium of the aging rat 104 8.3.2 Parenchymal lung structure in the aging rat 105 8.3.3 Alveolar tissue compartments 106 8.4 Conclusion 110 Acknowledgments 110 References 111 9 Mouse Models to Explore the Aging Lung 117 Mingyi Wang and Deepak A. Deshpande 9.1 Pulmonary changes during aging 117 9.1.1 Advantages of mouse models for studying physiological lung changes 118 9.2 Key findings from mouse models of aging 119 9.2.1 Longevity and lung function in mice 120 9.2.2 Different strains of mice have different alterations in lung mechanics 120 9.2.3 Transgenic mouse model to study aging in the lungs 121 9.3 Age is a risk factor for obstructive pulmonary diseases 123 9.4 Challenges ahead 124 9.5 Conclusion 125 Acknowledgments 126 References 126 10 Evidence for Premature Lung Aging of the Injured Neonatal Lung as Exemplified by Bronchopulmonary Dysplasia 131 Anne Hilgendorff 10.1 Introducing bronchopulmonary dysplasia 131 10.2 Altered pulmonary function in infants with BPD 132 10.3 Response to injury 133 10.3.1 Oxidative stress response 134 10.3.2 Extracellular matrix remodeling 136 10.3.3 Inflammation 136 10.3.4 Morphogenetic response 137 10.4 Prenatal and genetic predisposition 137 10.5 Conclusion 138 References 138 11 Remodeling of the Extracellular Matrix in the Aging Lung 145 Jesse Roman 11.1 Introduction 145 11.2 The aging lung 145 11.3 Activation of tissue remodeling in the senescent lung 146 11.4 The aging lung fibroblast 148 11.5 Potential role of oxidant stress in triggering remodeling in the aging lung 149 11.6 Implications for remodeling of the lung extracellular matrix in the aged lung 150 11.7 Conclusions 152 Acknowledgments 154 References 154 12 Aging Mesenchymal Stem Cells in Lung Disease 159 Maria G. Kapetanaki, Ana L. Mora, and Mauricio Rojas 12.1 Aging and lung diseases 159 12.2 Mesenchymal stem cells (MSCs) 160 12.2.1 Description of MSCs 160 12.2.2 Characterization of MSCs 160 12.2.3 Functional properties of MSCs 161 12.3 Impact of aging on mesenchymal stem cells 162 12.3.1 In vitro aging of MSCs 162 12.3.2 Age-related changes in B-MSCs 163 12.3.3 Aging of B-MSCs versus aging of the organism 163 12.4 B-MSCs in disease 164 12.5 B-MSCs in therapy 166 12.5.1 Ex vivo expansion 166 12.5.2 Conditions affecting the expansion 167 12.5.3 Autologous versus allogeneic B-MSCs 167 12.5.4 Combination of cell preparations 167 12.5.5 Delivery and targeting 167 12.6 Conclusion 167 Acknowledgments 168 References 168 13 COPD as a Disease of Premature Aging 173 Laurent Boyer, Jorge Boczkowski, and Serge Adnot 13.1 Introduction 173 13.2 Senescent cells contribute to the pathogenesis of COPD 174 13.2.1 Accumulation of senescent cells in COPD lungs 174 13.2.2 Inflammation and lung-cell senescence in COPD 175 13.2.3 Emphysema and lung-cell senescence in COPD 176 13.2.4 Pulmonary hypertension and cell senescence in COPD 177 13.3 Lung dysfunction and the general process of premature aging in COPD 179 13.3.1 Clinical manifestations of premature aging in COPD patients 179 13.3.2 Role for lung alterations in systemic premature aging during COPD 180 13.4 Conclusion 181 References 181 14 Lung Infections and Aging 185 Jacqueline M. Kruser and Keith C. Meyer 14.1 Introduction 185 14.2 Aging and immunosenescence 185 14.2.1 Innate immunity 187 14.2.2 Adaptive immunity 188 14.2.3 Autoimmunity 189 14.2.4 Lung-specific changes in immunity with aging 190 14.3 Inflamm-aging and susceptibility to infection 190 14.4 Respiratory infection and regulation of host responses 192 14.5 Preventing respiratory infection 194 14.6 Summary and conclusions 195 References 195 Index 201

About the Author :
Dr. Mauricio Rojas is an Assistant Professor in the Division of Pulmonary, Allergy and Critical Care Medicine, Department of Medicine, University of Pittsburgh. Silke Meiners, PhD is a Research Group Leader from the Comprehensive Pneumology Center in Munich. Claude Jourdan Le Saux, PhD is an Assistant Professor in the Department of Medicine Division of Cardiology/Pulmonary and Critical Care, University of Texas Health Science Center at San Antonio, San Antonio, Texas, as well as a faculty member of the Barshop Institute for Longevity and Aging Studies Nathan Shock Aging Center of Excellence and Department of Cellular and Structural Biology.