Less Can Be More: The Hormesis Theory of Stress Adaptation in the Global Biosphere and Its Implications.
Volker SchirrmacherPublished in: Biomedicines (2021)
A dose-response relationship to stressors, according to the hormesis theory, is characterized by low-dose stimulation and high-dose inhibition. It is non-linear with a low-dose optimum. Stress responses by cells lead to adapted vitality and fitness. Physical stress can be exerted through heat, radiation, or physical exercise. Chemical stressors include reactive species from oxygen (ROS), nitrogen (RNS), and carbon (RCS), carcinogens, elements, such as lithium (Li) and silicon (Si), and metals, such as silver (Ag), cadmium (Cd), and lead (Pb). Anthropogenic chemicals are agrochemicals (phytotoxins, herbicides), industrial chemicals, and pharmaceuticals. Biochemical stress can be exerted through toxins, medical drugs (e.g., cytostatics, psychopharmaceuticals, non-steroidal inhibitors of inflammation), and through fasting (dietary restriction). Key-lock interactions between enzymes and substrates, antigens and antibodies, antigen-presenting cells, and cognate T cells are the basics of biology, biochemistry, and immunology. Their rules do not obey linear dose-response relationships. The review provides examples of biologic stressors: oncolytic viruses (e.g., immuno-virotherapy of cancer) and hormones (e.g., melatonin, stress hormones). Molecular mechanisms of cellular stress adaptation involve the protein quality control system (PQS) and homeostasis of proteasome, endoplasmic reticulum, and mitochondria. Important components are transcription factors (e.g., Nrf2), micro-RNAs, heat shock proteins, ionic calcium, and enzymes (e.g., glutathion redox enzymes, DNA methyltransferases, and DNA repair enzymes). Cellular growth control, intercellular communication, and resistance to stress from microbial infections involve growth factors, cytokines, chemokines, interferons, and their respective receptors. The effects of hormesis during evolution are multifarious: cell protection and survival, evolutionary flexibility, and epigenetic memory. According to the hormesis theory, this is true for the entire biosphere, e.g., archaia, bacteria, fungi, plants, and the animal kingdoms.
Keyphrases
- low dose
- high dose
- heat shock
- dna repair
- oxidative stress
- endoplasmic reticulum
- heat stress
- dna damage
- induced apoptosis
- healthcare
- heavy metals
- stress induced
- physical activity
- transcription factor
- cell death
- rheumatoid arthritis
- stem cells
- dna methylation
- endoplasmic reticulum stress
- cell cycle arrest
- single molecule
- cell free
- small molecule
- squamous cell carcinoma
- cell proliferation
- case report
- protein protein
- cell therapy
- quantum dots
- mental health
- genome wide
- heat shock protein
- risk assessment
- immune response
- human health
- highly efficient
- metabolic syndrome
- dna binding
- squamous cell