Physical bioenergetics of degradation-resistant proteins in diseases and aging

Medical Hypotheses (1998) 51, 47-5 l © Harcourt Brace & Co. Ltd 1998

Physical bioenergetics of degradation-resistant proteins in diseases and aging S. AXELSSON In association with the Department of Obstetrics and Gynaecology, Swedish University of Agricultural Sciences, S 75007 Uppsala, Sweden. Correspondence to: Sven Axelsson, S-615 32 Valdemarsvik, Sweden (Fax: +46 123 10429)

A b s t r a c t - The characteristics of degradation-resistant proteins (prions) suggested a primary physical and then bioenergetic conversion by a fundamental chiral change in one or a few amino acids. The insolubility of heterochiral proteins (chirons) results in protein dysfunction. These inert proteins are logically neither contagious or transmissible, nor of genetic nature. Conformational species of chirons will arise by varied position and kind of converted amino acid(s). Cellular damage will depend on intensity and duration of activity in the cholinergic and immune systems, which are characterized by very high localization specificity and genetic variability. The long-term pathological changes will be general shrinking, sclerotizing and wasting as in AIDS and aging. The impaired immune function and the continuous gene activation may result in .,---q;~oration and tumorigenesis. Comparison between infections revealed possible routes of transmission and pathophysiology in spongifom encephalopathies in man and animals. Also, a plausible epidemiology was suggested for these diseases in ruminants (BSE and scrapie) in the UK. Preventive and therapeutic measures are briefly discussed. The headlines of the present concept were naturally related to basic conditions of life given by quantum physics, intrinsic membrane entropy and the dimension of time.

Introduction

The formation of degradation-resistant proteins is a common phenomenon in many neurodegenerative disorders and in aging. Such converted proteins (prions) are also found in the chronic human and animal CNS diseases of the scrapie-type. A unifying theory is lacking concerning the post-translational, competitive conversion of normal membrane proteins into intracellular, cytoskeleton-binding, heat- and protease-resistant isoforms. A probable explanation

for this type of change is a fundamental chiral conversion in one or a few amino acids. Reasonable answers can then be given to questions of causes and genetics and concerning the alarming possibility of infectivity and transmission. To avoid the assumption that heterochiral proteins are infectious agents, they are here termed 'chirons'. The normal membrane protein is called 'chiron precursor protein' (CPP) by analogy with the amyloid precursor protein (APP) in, for instance, Alzheimer's disease (AD).

Received 27 November 1996 Accepted 13 May 1997

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Chirality and chirons Chirality or handedness exists at all levels in the universe, ultimately as a break in symmetry because of factors in the fields of quantum physics. The electroweak force between electrons and nucleons in atoms is one evident level of left-right asymmetry changes (1). Chirality is a property of atoms. So, regions of differing chirality and energy content can exist within the same molecule. An important feature of chirality is that the L- and D-forms compete and that the dominating form is favoured. Other aspects are the lower energy content of L-forms, the time scales (years, decades) of some chiral changes, and the chiral lability of carbon atoms (2). Higher biological life is dominated by L-amino acids and Dnucleic acids combined with D-sugars, while lower organisms and larvae and pupae of some insects use D-amino acids.

Heterochirality The labile asymmetric carbon atoms in the side chains of amino acids (except Gly) give reversible enantiomeres in both the L- and D-forms. However, heteroenantiomeric proteins and amino-acidsubstituted homochiral proteins are not resistant against solubilization and degradation. So, the o~carbons of the peptide backbones are the most likely chiral centers of degradation-resistant proteins. The result will be a greater physical momentum with strong stability. Then, a single or a few physically altered chiral amino acids can compete with normal proteins such as CPP and APP. A mixture of L- and D-amino acids do not produce proteins with the m-helix folding needed for effective catalysis. The strong hydrophobicity of chirons also prevents hydrodynamic interactions, which are known to increase functional order of proteins at the expense of increased disorder of water. Degradation of chirons by chemicals, by the strong protease-K and by heating only produce truncated peptides with loss of membrane anchor and glycosylation. Many features of chirons are relevant to the understanding of scrapietype diseases. However, it is easy to get the impression that chirons are products rather than causes.

Chiron bioenergetics A primary physical input of energy is necessary for the chiral conversion of amino acids in homochiral L-proteins. The energy may come from changes in photonic, electronic and deeper quantum fields.

MEDICAL HYPOTHESES

Random autocatalysis, beta-particle and UV radiation and electromagnetism can serve as sources. However, the rate of such a physical conversion is very low. It has been estimated to about one part in 109 or l011 (1). When they do not participate in metabolic activity, amino acids will slowly racemize towards chiral parity (3). Biological life requires continual input of energy. The main part comes from the transformation of photonic into electronic energy. Generally, energetics of living organisms can be understood as the transfer of electrons between molecules. The most powerful conveyor of primary energetic activation signals is acetylcholine (ACh). Therefore, the cholinergic system is most probably involved in the formation of chirons on the template of one or a few physically altered amino acids. There are accordingly clear features of cholinergic dysfunction in most neurological diseases and in aging. The main flow of energy in activations is the phosphate bond transfer of electrons and also a continuous excess of waterinsoluble free electrons that gives electrical currents (miniature endplate potentials, EMG, EKG, EEG). The energy-rich esterbond of ACh also contributes energy and so do many other hydrolytic and phospholipatic processes. Dissipation of heat and photons will balance excessive energy production.

Cellular damage and c~rons Main features of cellular damage are the release of lipids and their polar bead groups such as choline (4). The process is sometimes called 'auto-cannibalism' because of the preference to acetylate choline (Ch) to ACh before repairing disordered membranes (5). In contrast to other signalling systems, the cholinergic system degrades its transmitter, ACh, outside or on the cell membrane by cholinesterase (ChE) hydrolysis. Thus, disordered cell membranes, even those lacking specialized cholinergic receptors (paraneurons), may be the first place for a one-electron reduction of oxygen and the formation of potentially harmful oxygen intermediates. These free radicals with unpaired electrons are believed to affect the conversion of CPP (6). Exocytosis of ACh is directly coupled to endocytosis (7) and may include CPP. Slowly, chirons will dominate and contribute to dysfunction and cell death by preventing normal protein functions. For example, the post-translational conversion of APP peptides in Alzheimer's disease results in ~-sheet configuration, degradation resistance and hydrophobicity (8). Accordingly, the amyloidogenic process was found to depend on conversion of L-Asp residues to resistant D-Asp forms (9). The tendency

PHYSICAL BIOENERGETICS OF DEGRADATION-RESISTANTPROTEINS IN DISEASES AND AGING

to undergo chiral conversion differs between individual amino acids, Asp being the most sensitive. This can explain the existence of various conformational species of chirons. The position of chiral defects in the peptide sequences is another source of diversity. The chiral lability of Asp may also affect many evolutionary related enzymes and structural proteins possessing ChE-like domains and catalytically essential Asp residues (10). There are also clinically important vascular amyloid variants in scrapie-type diseases.

Chiron genetics The normally encoded and expressed CPP is the substrate for chiron formation, and the encoding nucleic acids must be produced by normally functioning homochiral proteins of either L- or D-form. Genes for chiron expression do not exist. Furthermore, chirally defective informational carders (DNA, RNA) cannot serve as a matrix for replication, in contrast to genes for mutated proteins (11). The physicochemical difference is that chirons are degradation resistant, while mutated proteins are not. Clearly, the posttranslational chirons will not have a genetic basis, nor be the result of a chiral change in nucleic acids.

Cholinergic genetics and priority Polymorphic components and their distribution in the cholinergic and immune systems confer highly varied, MHC (HLA in humans) associated, genetic disposition, localization specificity and autoimmunity. These features are main characteristics in most neurodegenerative conditions such as AD and other aging dementias. The cholinergic neural network in the CNS governs gene expression within minutes (12) and is to a large extent autonomous as in the CNS and also in the immune system. Immune cells have been regarded as circulating or stationary synapses (13). Cholinergic components (5,14,15) make them a part of the cholinergic system. The general priority of the cholinergic system and distributions of its components are important aspects. It is facts about localization and dependence of ACh that determine further functional sequences. For example, catecholamines are in essence a subordered division, activated by ACh signalling in the CNS and in the adrenals. This is important in, for instance, evaluation of mental stress conditions. To give another example, all measured neurotransmitters, hormones and neuropeptides in parts of the CNS were influenced when ACh concentrations were increased by ChE inhibition in the CNS (16).

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Transmission and infectivity of chirons in diseases Chirons are primarily physical and bioenergetic products, not infectious agents. Intracerebral inoculations and surgical accidents circumvent the most crucial aspects of how natural transmission of chirons could possibly occur. Ingested chirons are not broken down to amino acids and will thus remain in the digestive canal and be discharged from it with faeces. Only newborn calves resorb whole proteins, and this might possibly occur also in adults with digestive disorders. However, chirons present in the blood will be engulfed by phagocytic cells. Again, the chirons are indigestible. As a result of macrophage migration, they will form deposits in various parts of the body. Astrogliosis, affecting brain macrophages, illustrates this mechanism, possibly causing some glial dysfunction. Thus, transmission of chirons by the oral route appears unlikely. Both ingested and parenterally adminstered chirons will eventually be trapped by stationary or circulating antigen-presenting cells of the monocyte-macrophage lineage. Chirons are inert and are not processed and presented as antigenic peptides to T-cells. So, no immune-cholinergic activation occurs and no energy for chiron formation is delivered. However, the cholinergic motif of the immune system widens the disease panorama very much. In short, both immune cells and neurons will die upon chiron formation but not by chiron transmission.

Pathogenesis and chiron formation The cannibalistic human spongiform encephalopathy known as 'Kuru' may serve as model. Men, who ate musculature only, did not acquire clinically manifest disease. Children and females affected by the disease had repeatedly smeared brain tissue from dead tribe members on their bodies. Infective agents penetrating through skin cuts and mucous membrane erosions will be captured by the CD4-bearing dendritic cells located in skin and mucosal surfaces of the body. They are then presented to T4 helper cells. T-cells and antibody-producing B-cells became activated and also cooperate in antibody-dependent cellular cytotoxicity (ADCC). Carcass chirons are inert to the immune system. During many years of repeated ceremonial exposure, the immune system became increasingly efficient with aspect to antibody neutralization of circulating infectious microorganisms and in eliminating virus-infected cells. This persistent immunocholinergic activation will result in continuous cellular damage, chiron formation, and death of T4 cells and CD4 macrophages. The general

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activation of the adaptive immunocholinergic system will also provide energy for accelerated chiron conversions and cellular death in the CNS. Then, the depletion of the functionally crucial T4 helper cells impairs the whole immune function. The overload of inert chirons in macrophages will contribute to immune dysfunction by defective presentation of degradable antigens. No cases of Kuru occurred in neighbouring tribes with the same ritual habits. So, priming local physical conditions and endemic infectious agents may represent two etiological factors. Also, immunocholinergic genetic disposition may affect chiron formation, which must not be interpreted as genetic chiron expression. An aggressive personality (A-type) may have a low threshold of cholinergic activation.

MEDICAL HYPOTHESES

Applied ehiron aspects The chiron concept may also be relevant with respect to 'the protein error theory of aging' (18). The elderly may be a source of heterochiral proteins. For example, routine surgery provides cataract lenses and cutaneous and arthritic hyperplasias. Atherosclerotic plaques and tumors will also be of medical interest. AIDS patients can provide damaged T4 lymphocytes, follicular dendritic cells and tumour tissues. Peripheral chirons will probably reflect the degree of chiral defects in the CNS. The predestined shrinking, sclerotizing and wasting in aging and in diseases such as AIDS could be explained by the increase of proteins that are incapable of the functionally indispensable interaction with water. A few aspects of prevention and treatment

Persistent infections Repeated infections causing lasting immune activations are of course common phenomena in a variety of diseases. Most thoroughly investigated is AIDS, which shares features of Kuru. The mucocutaneous infection route and the long-term effects on the immune system are similar, and primary dementia and cognitive and motor dysfunctions in AIDS suggest neuronal damage and chiron formation in the CNS. The perinatal transmission of HIV and other viruses must be distinguished from chiron transmission. Virus infections will contribute to protein deterioration by causing cholinergism like all other integrity threats to the body. AIDS may occur without HIV infections, and there are HIV infections without accompanying AIDS (17). In the asymptomatic phase, low numbers of viruses are replicating within a few cells. Eventually, the vital immune surveillance will become defective, such as in children and female Kuru, and leave room for opportunistic infections and increased virus replication. Also the cytotoxic control of neoplastic cells will fail as suggested by the many types of neoplasias which occur in HIV and other lentiviral infections. An example of life-persistent infection in ruminants is the widespread infection with bovine diarrhoea virus (BDV), also causing border disease in sheep. Like HIV infections these diseases have been thouroughly investigated. The transmission routes of BDV infections may be of high significance in the enigmatic epidemiology of ruminant spongiform encephalopathies (BSE and scrapie) in the UK. As in HIV infection, the intrauterine and postpartum infection routes of BDV and other common viruses should not be mistaken for chiron transmission.

Preventive measures are possible against local radioactivity, electromagnetism and excessive sunburning. The sometimes very obvious endemic occurrence of chiron-producing diseases should therefore first be studied from the physical point of view, but this will probably be of low significance compared with mental and physiological cholinergic dysfunctions by diverse causes. Immune and cholinergic mechanisms are always ongoing and basically essential for life. High intensity and/or duration will make them harmful. Thus, chirons could be regarded as ashes of physically induced biological burning. The time factor is involved not only in aging but also in diseases. While isolated integrity challenges such as infections and vaccinations have protective effects through activation of the immune system, chronic and repeated exposures are obviously detrimental. Accordingly, it is never too late to reduce risk exposure. For example, behavioural changes stopped female and children Kuru, can explain the existence of HIVinfected long-term nonprogressors to AIDS (19), and normalization by discontinued smoking of the risk of high tumour incidence from combined toxic and chronic nicotinic cholinergic activation. Cholinesterase inhibitors (e.g. tacrine) produce 'cholinergism', and may be of some therapeutic value in late anergic stages of AD. Given earlier on mere suspicion, this treatment may be detrimental instead of ameliorating. Besides, Alzheimer's disease appears to be heterogeneous (19), reflecting chiron formation in a lot of proteins, most probably in the crucial moderating ChEs. Polyanionic glycans such as dextran sulphate could be of some value in treatment. These compounds which increase endocytosis of CPP (20) might conceivably favour the intracellular, com-

PHYSICALBIOENERGETICSOF DEGRADATION-RESISTANTPROTEINS IN DISEASESAND AGING

petitive balance over chirons. Further therapeutic considerations must await an urgent updating of immunocholinergic pathology.

Life conditions and chirons Ultimately, life is subject to the laws of nature. First, in spite of uncertainties in the electroweak quantum field physics, elementary chiral changes may depend on particle preference for left or right orbiting and/or spin directions. Second, chirons are products of the intrinsic necessity to use the life-essential but also cytotoxic and potentially deadly ACh to draw energy from the universal entropy tendency. The third dimension is time. It is of decisive importance in cholinergic pathology and explicit in aging.

Acknowledgement I wish to thank Prof. Hans Kindahl at the Dept of Obstetrics and Gynaecology for encouraging discussions and for initiating further experimental approaches to prove the hypothesis.

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