Hormonal imprinting is an epigenetic process which is taking place perinatally at the first encounter between the developing hormone receptors and their target hormones. The hormonal imprinting influences the binding capacity of receptors, the hormone synthesis of the cells, and other hormonally regulated functions, as sexual behavior, aggressivity, empathy, etc. However, during the critical period, when the window for imprinting is open, molecules similar to the physiological imprinters as synthetic hormone analogs, other members of the hormone families, environmental pollutants, etc. can cause faulty imprinting with life-long consequences. The developing immune system, the cells of which also have receptors for hormones, is very sensitive to faulty imprinting, which causes alterations in the antibody and cytokine production, in the ratio of immune cells, in the defense against bacterial and viral infections as well as against malginant tumors. Immune cells (lymphocytes, monocytes, granulocytes and mast cells) are also producing hormones which are secreted into the blood circulation as well as are transported locally (packed transport). This process is also disturbed by faulty imprinting. As immune cells are differentiating during the whole life, faulty imprinting could develop any time, however, the most decisive is the perinatal imprinting. The faulty imprinting is inherited to the progenies in general and especially in the case of immune system. In our modern world the number and amount of arteficial imprinters (e.g. endocrine disruptors and drugs) are enormously increasing. The effects of the faulty imprinters most dangerous to the immune system are shown in the paper. The present and future consequences of the flood of faulty imprintings are unpredictable however, it is discussed.
According to experimental data, eukaryote unicellulars are able to learn, have immunity and memory. Learning is carried out in a very primitive form, and the memory is not neural but an epigenetic one. However, this epigenetic memory, which is well justified by the presence and manifestation of hormonal imprinting, is strong and permanent in the life of cell and also in its progenies. This memory is epigenetically executed by the alteration and fixation of methylation pattern of genes without changes in base sequences. The immunity of unicellulars is based on self/non-self discrimination, which leads to the destruction of non-self invaders and utilization of them as nourishment (by phagocytosis). The tools of learning, memory, and immunity of unicellulars are uniformly found in plasma membrane receptors, which formed under the effect of dynamic receptor pattern generation, suggested by Koch et al., and this is the basis of hormonal imprinting, by which the encounter between a chemical substance and the cell is specifically memorized. The receptors and imprinting are also used in the later steps of evolution up to mammals (including man) in each mentioned functions. This means that learning, memory, and immunity can be deduced to a unicellular eukaryote level.
Fogamzás alkalmával a gének által meghatározottan egy új egyed jön létre,
amelynek struktúráját és tulajdonságait (működését, a részletek együttműködését
és annak időbeliségét, valamint erősségét (expresszivitását) gének feletti
(epigenetikus) szabályozás rendezi, mely program formájában rögzül. Ez a program
folyamatosan alakul és alakítható, miközben hibák történhetnek, melyek a program
tartós elemeivé válnak, illetve megzavarják a fiziológiás program működését.
Vannak az élet folyamán különösen érzékeny periódusok (mint a perinatalis
(praenatalis – fetalis-neonatalis, korai postnatalis időszak), amikor az
epigenetikus hatások (imprinting) fiziológiásan rögzülnek, és ezek közé
sorolható a pubertás időszaka is. Ugyanakkor az átprogramozás nincs időkorlátok
közé szorítva, hanem a sejtek fejlődési állapotától függ, így differenciálódó
sejtekben (sejtcsoportokban) bármely életkorban megtörténhet. Az átprogramozott
sejtek ezután az új programnak megfelelően funkcionálnak, az élet végéig. Ez az
adott életfunkció normálistól való eltéréséhez, tartós meggyengüléséhez vagy
éppen megerősödéséhez vezethet, de akár (a normális szabályozásból kiszakadva)
daganatképződés alapja is lehet. A programozásban és átprogramozásban alapvető
szerepe van az endokrin rendszernek (hormonoknak), így a környezetünkben
megjelenő hormonszerű molekulák (endokrin diszruptorok) képesek életreszólóan
megzavarni a programot, ami a hibás hormonális imprinting, illetve a DOHaD
(Developmental Origin of Health and Disease) teóriájában nyeri el magyarázatát.
Az átalakult (hibás) program az utódgenerációkra átöröklődik. Míg a
perinatalisan fellépő, de csak később megnyilvánuló zavar már többé-kevésbé
ismertnek és elismertnek tűnik (a hibás hormonális imprinting és a DOHaD
teóriája), a későbbi életkorokban (elsősorban pubertáskorban), de bármely
életkorban differenciálódó sejtekben történő átprogramozódás kevésbé ismert,
pedig hasonló problémákat okozhat. A megváltozott program az utódgenerációkra
öröklődik, és az utódban már ennek további átprogramozódása történik meg.
Mindezt figyelembe véve az endokrin diszruptorok provokálta – felnőttkorban
fellépő – betegségek szaporodása várható. Orv Hetil. 2020; 161(25):
The unicellular ciliate Tetrahymena is a complete organism, one of the most highly developed protozoans, which has specialized organelles performing each of the functions characteristic to the cells of higher ranked animals. It is also able to produce, store, and secrete hormones of higher ranked animals and also react to them. It produces lectins that can bind them and has functions, which are influenced by exogenous lectins. The review lists the observations on the relationship between lectins and Tetrahymena and try to construe them on the basis of the data, which are at our disposal. Considering the data, lectins can be used by Tetrahymena as materials for influencing conjugation, for stimulating hormone receptors, and by this, mimic the hormonal functions. Lectins can influence phagocytosis and movement of the cells as well as the cell division. As Tetrahymena can recognize both related and hostile cells by the help of lectins and surface sugars, it could be surmised a complex predator–prey system. This could determine the survival of the population as well as the nourishment conditions. When Tetrahymena is pathogenic, it can use lectins as virulence factors.
Hormones, characteristic to higher ranked animals, are synthesized, stored, and secreted by unicellular eukaryote animals. The unicells also have receptors for recognizing these materials and transmit the message into the cells for provoking response. The hormones are effective in very low concentrations (down to 10–21 M) and opposite effects of lower and higher concentrations can be observed. However, sometimes linear concentration effects can be found, which means that hormesis exists, nevertheless uncertain, as it is in the phase of formation (evolutionary experimentation). Hormesis, by transformation (fixation) of cytoplasmic receptor-like membrane components to receptors in the presence of the given hormone, likely helps the development of unicellular endocrine character and by this the evolution of endocrine system. The effect by extremely low concentrations of hormones had been forced by the watery way of unicellular life, which could establish the physiological concentrations of hormones in the blood of higher ranked animals. This means that hormetic low doses are the normal, effective concentrations and the high concentrations are artificial, consequently could be dangerous.
The mast cell is a member of the immune system having a basic role in allergic (anaphylactic) reactions. However, it contains, synthesizes, stores and secretes lots of substances, which initiates other reactions or participates in them. These are in connection with the deterioration of tissue correlation, as malignant tumors, angiogenesis, wound healing, pregnancy and different pathological conditions. In addition — as other members of the immune system — mast cells can synthesize, store and secrete hormones characteristic to the endocrine glands and can transport them to the site of requirement (packed transport), or produce and employ them locally. The effect of mast cells is controversial and frequently dual, stimulatory or inhibitory to the same organ or process. This is likely due to the heterogeneity of the mast cells, in morphology and cell content alike and dependent on the actual condition of the targeted tissue. The cells are transported in an unmatured form by the blood circulation and are exposed to microenvironmental effects, which influence their maturation. Their enrichment around tumors suggested using them as targets for tumor therapy more than fifty years ago (by the author), however, this idea lives its renaissance now. The review discusses the facts and ideas critically.
The unicellular eukaryote Tetrahymena synthesize, store and secrete biogenic amines (histamine, serotonin, epinephrine, dopamine, melatonin) and also can take up amines from the milieu. It also has (G-protein-coupled) receptors (binding sites) for these amines as well, as second messengers. The factors infuencing the mentioned processes are shown. For certain amines the genes and the coded enzymes are demonstrated. The amines influence phagocytosis, cell division, ciliary regeneration, glucose metabolism and chemotaxis. There are interhormone actions between the amines, and between the amines and other hormones produced by Tetrahymena. The critical review discusses the role of amines in the early stages of evolution and compares this to their functions in mammals. It tries to give answer how and why biogenic amines were selected to hormones, and why new functions formed for them in higher ranked animals, preserving also the ancient ones.
The unicellular ciliate, Tetrahymena has receptors for hormones of the higher ranked animals, these hormones (e.g. insulin, triiodothyronine, ACTH, histamine, etc.) are also produced by it and it has signal pathways and second messengers for signal transmission. These components are chemically and functionally very similar to that of mammalian ones. The exogenously given hormones regulate different functions, as movement, phagocytosis, chemotaxis, cell growth, secretion, excretion and the cells’ own hormone production. The receptors are extremely sensitive, certain hormones are sensed (and response is provoked) at 10−21 M concentration, which makes likely that the function could work by the effect of hormones produced by the Tetrahymena itself. The signal reception is selective, it can differentiate between closely related hormones. The review is listing the hormones produced by the Tetrahymena, the receptors which can receive signals and the signal pathways and second messengers as well, as the known effects of mammalian hormones to the life functions of Tetrahymena. The possible and justified role of hormonal system in the Tetrahymena as a single cell and inside the Tetrahymena population, as a community is discussed. The unicellular hormonal system and mammalian endocrine system are compared and evolutionary conclusions are drawn.
The first observation on the relationship between the pineal gland and the immune system was done by the author of this paper in the late sixties and early seventies of the last century. After neonatal pinealectomy the thymus has been destroyed and wasting disease developed. Since that time a flood of experiments justified the observation and pointed to the prominent role of pineal in the regulation of the immune system. Melatonin, the hormone of the pineal gland stimulates immune processes acting to the immune cells’ cytokine production, the haemopoiesis, and immune cell-target cell interactions. Melatonin receptors have been demonstrated and their localization and function were justified. Melatonin production by and melatonin receptors on (and in) the immune cells was proved. Melatonin agonists have been synthesized and the use of melatonin as adjuvant in the therapy of diseases connected to the immune system (cancers included) has been started. The paper summarizes the most important studies and discusses the interrelations of the data. The discussion points to the possibility of packed transport of the pineal hormone by the immune cells and to the adventages of local regulation by this transport.
Ah-receptors (AhRs) recognize and bind foreign environmental molecules as well as some
target hormones of other nuclear receptors. As ligands activate transcription factors,
they transmit the information on the presence of these molecules by binding to the DNA,
which in turn activate xenobiotic metabolism genes. Cross talk with other nuclear
receptors or some non-nuclear receptors also activates or inhibits endocrine processes.
Immune cells have AhRs by which they are activated for physiological (immunity) or
non-physiological (allergy and autoimmunity) processes. They can be imprinted by hormonal
or pseudo-hormonal (environmental) factors, which could provoke pathological alterations
for life (by faulty perinatal hormonal imprinting). The variety and amount of human-made
new environmental molecules (endocrine disruptors) are enormously growing, so the
importance of AhR functions is also expanding.