Genetically Programmed Cell Death: Concepts of Death and Immortality in the Age of the Genome
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Christian Spirituality and Science Issues in the Contemporary World Volume 9 Issue 1 Subjective Reality, Complexity and Article 3 Programmed Cell Death 2013 Genetically Programmed Cell Death: Concepts of Death and Immortality in the Age of the Genome Paul U. Cameron Monash University, [email protected] Lynden Rogers Avondale College of Higher Education, [email protected] Follow this and additional works at: https://research.avondale.edu.au/css Recommended Citation Cameron, P. U., & Rogers, L. (2013). Genetically programmed cell death: Concepts of death and immortality in the age of the genome. Christian Spirituality and Science, 9(1), 32-55. Retrieved from https://research.avondale.edu.au/css/vol9/iss1/3 This Article is brought to you for free and open access by the Avondale Centre for Interdisciplinary Studies in Science at ResearchOnline@Avondale. It has been accepted for inclusion in Christian Spirituality and Science by an authorized editor of ResearchOnline@Avondale. For more information, please contact [email protected]. Cameron and Rogers: Genetically Programmed Cell Death: Concepts of Death and Immortal Genetically Programmed Cell Death: Concepts of Death and Immortality in the Age of the Genome. Associate Professor Paul U Cameron, Clinical Immunologist and Immunopathologist Infectious Diseases Department, Monash University Pathology Department, Alfred Hospital Infectious Diseases Unit, Alfred Hospital Melbourne, Victoria and Lynden J Rogers School of Science and Mathematics Avondale College of Higher Education Cooranbong, NSW ABSTRACT Scientific discoveries have done much to complicate matters of life and death. Perhaps the most significant such revelation in recent decades has been that every cell in our bodies has a built-in, and genetically controlled suicide capability. This is also true of most other organisms. Cells know how to die! It has been discovered that programmed cell death turns out to be vitally important in many life processes such as: the development of the mature organism from a single cell, combatting foreign threats, such as infections, and controlling rampant cell growth, as found in various cancers. It is also important in the normal regeneration of skin and gut lining. Cell death appears to be much more inextricably intertwined with life than may have been earlier supposed. This paper introduces this discussion and explores some of the implications of programmed cell death for a Christian understanding of the relationship between life and death. Keywords: necrosis, programmed cell death, apoptosis, immunity 1. INTRODUCTION death and sorrow are no more, there One of the dominant motifs woven is an underlying concept of death as through the Judeo-Chri stian world an enemy from which humans can view is that of death as the ultimate be saved.3 Indeed, one of the best expression of evil, a foe that must and known verses in the canon, John 3:16, will be overcome.1 From the Genesis encapsulates this view.4 Furthermore, account of the fall and the expulsion many Christians understand not just from Eden2 through to the Revela- human death but death in any form and tion account of a new world where under all circumstances, to be a result 32 Published by ResearchOnline@Avondale, 2013 1 Christian Spirituality and Science, Vol. 9 [2013], Iss. 1, Art. 3 of sin’s “curse”. However, it may be by the realisation that the outer layers asked how well this view of death as of skin, for example, are comprised of the ultimate enemy accords with the dead cells. observations of modern biology. All this has changed. Biological 2. ISSUES OF LIFE AND science has revealed that all living DEATH organisms, both plants and animals, are There is considerable evidence to sug- composed of small basic units called gest that the idea of death in biblical cells. These work in similar ways in times was very simple and was associ- plants and animals and are fundamen- ated only with the world of animals and tal to all processes of life and death for humans. Animals were either “quick” both. We also now recognise the exist- (moving) or “dead”, as in Acts 10:425. ence of a huge host of microorganisms. Certainly, life and death were holistic Some of these are beneficial, even in that these states applied to the whole essential, to higher life forms while organism at once. Texts such as Gen others are deadly. Furthermore, we 9:4, Lev 17:13, 14 and Deut 12:236 understand that living entities utilise suggest also that, for the Hebrews, many dead cells, such as those found life was closely associated with blood. in the outer layer of skin, in their quest Indeed, the whole sanctuary ritual re- for survival, and continually produce flected this understanding. This may them. So in this sense even living suggest that only animals with blood things are not completely “alive”. Of were regarded as being alive. Inter- course, science still has much to learn estingly, some evidence suggests that about life and death. Viruses provide plants, being stationary in any case, an illustration of the difficulty of actu- were not thought of as being alive or ally defining life. Although possessing dead in the same way as were animals; a small amount of either DNA or RNA they were either “green” or “dry”.7 contained within a protein coat, they do Clearly, such an understanding would not have any intrinsic metabolism and have allowed the animals and humans replicate only inside the cells of other in the Garden of Eden, all of which ac- organisms. For these reasons they are cording to the literal reading of the text not regarded as actually being “alive”. were vegetarian, to eat without causing Additionally, Australia has many fasci- death. That such ingestion and diges- nating life forms, such as cryptobiotic tion may have involved the systematic midge larvae, which can lie dormant elimination of microorganisms within and desiccated for years under dry the gut represented no problem since outback river beds, to all intents and all such processes were invisible to purposes dead and showing no visible those in Bible times. Similarly, with sign of metabolism. Yet a sudden, no concept of the “cell”, they would soaking rain can “wake” them up, not have been theologically challenged whereupon they quickly become active 33 https://research.avondale.edu.au/css/vol9/iss1/3 2 Cameron and Rogers: Genetically Programmed Cell Death: Concepts of Death and Immortal and reproduce, all in the few days the ments or ecological niches, yet each puddles remain.8 Just what differenti- is quite restricted in the range of ates such an organism in a quiescent conditions it can tolerate.10 Mammals, state from one which is actually dead although successful in populating is not well understood at all. Such dis- various hostile environments because coveries have enormously complicated of their ability to generate body heat our comprehension of death. and their utilisation of various forms of insulation, have cellular building One breakthrough which has proved blocks which are particularly limited central to an understanding of many in this regard. Isolated mammalian areas of cell biology, including repro- cells are very fragile compared to, duction and immunology, concerns for example, bacteria, and can only the programmed death of cells. There exist momentarily outside the body. is now an explosion of scientific lit- Also, they die very easily if exposed erature on this topic. A milestone in to low temperatures, as evidenced by this understanding was marked by the the death of the fingers, toes or other awarding of the Nobel Prize in medi- extremities because of frostbite. Ex- cine in 2002 to John Sulston, Sydney posure to high temperature is similarly Brenner and Robert Horvitz for their damaging. Small children can suffer work on the genetic control of cell severe consequences from high fevers, development and death.9 What exactly while a rise in body temperature of as did these scientists do and why did little as 5 degrees C can produce heat their discoveries merit such recogni- stroke and death in hot, dry, desert tion? What is programmed cell death environments. Many bear the scars and why is it so significant? What is of encounters with hot objects such the relationship between death at the as boiling water, stove hotplates or single cellular level and the death of fires. These result from the violent an organism? Finally, what are the death of individual cells making up implications of the existence of such a the affected tissue. biological system for our reading of the Genesis account, particularly concern- Such cell death results not only from ing the effect of early human history on physical damage but also from meta- death throughout the biosphere? This bolic insults such as exposure to carbon paper addresses these questions. First, monoxide (from car exhausts), cya- we need to differentiate between two nide, or the loss of nutrients − oxygen, main types of cell death. glucose, essential amino acids, protein components and vitamins. From what- 3. NECROSIS AND ever cause it may arise, this traumatic APOPTOSIS: DIFFERENT form of cell death is called “necrosis” TYPES OF CELL DEATH (Greek necros, meaning “dead body”). Living organisms are found within a relatively broad range of environ- But over the last 30 years biologists 34 Published by ResearchOnline@Avondale, 2013 3 Christian Spirituality and Science, Vol. 9 [2013], Iss. 1, Art. 3 have become aware of another, more may be seen under a microscope as a deliberate, mechanism of cell death, ruffling of the cell membrane which one quite distinct from necrosis. This proceeds to clumping or condensation is programmed cell death. John Kerr, of the cell nucleus and eventually to the an Australian pathologist whose inter- development of a featureless cell cyto- est was in cancer research, and his plasm with dense fragments of nuclei.