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Topic Review
Involvement of Bcl-2 Family Proteins in Tetraploidization-Related Senescence
The B-cell lymphoma 2 (Bcl-2) family of proteins is the main regulator of apoptosis. However, multiple emerging evidence has revealed that Bcl-2 family proteins are also involved in cellular senescence. On the one hand, the different expression of these proteins determines the entry into senescence. On the other hand, entry into senescence modulates the expression of these proteins, generally conferring resistance to apoptosis. With some exceptions, senescent cells are characterized by the upregulation of antiapoptotic proteins and downregulation of proapoptotic proteins. Under physiological conditions, freshly formed tetraploid cells die by apoptosis due to the tetraploidy checkpoint. However, suppression of Bcl-2 associated x protein (Bax), as well as overexpression of Bcl-2, favors the appearance and survival of tetraploid cells.
  • 487
  • 17 Apr 2023
Topic Review
Acute Psychosocial Stress Effects on Food Consumption
The most central physiological stress response is the activation of the hypothalamic-pituitary-adrenal (HPA) axis, which begins with the release of corticotrophin-releasing factor (CRF) from the hypothalamus. The physiological stress response can be dampened by eating, as the secretion of adrenocorticotropic hormone (ACTH) is reduced following consumption of food and the activation of the HPA axis is thereby attenuated.
  • 486
  • 27 Jun 2022
Topic Review
Carotenoids in Human Skin
Carotenoids having ≥10 π-π-conjugated C=C double bonds serve as an objective marker of the antioxidant status of human stratum corneum (SC) in vivo according to the principle: the higher the concentration of carotenoids the higher the antioxidant status of the entire SC. The exposure to doses of radiation in the visible (>50 J/cm2) and near-infrared (>120 J/cm2) spectral ranges cause the formation of free radicals in human skin, which can be determined in vivo by a decrease in the concentration of carotenoids in the SC. The topical application of sunscreen containing antioxidants has a protective effect on the skin. A diet containing antioxidants, in particular fruit and vegetables or food supplements, leads to an increase in the carotenoid concentration and the antioxidant status of the SC. The concentration of carotenoids in the SC can reflect the individual lifestyle habits and health status. Resonance Raman spectroscopy and diffuse reflectance spectroscopy are optical methods that provide a rapid and non-invasive screening of the kinetics of carotenoids and changes in the antioxidant status of the human SC, which can be useful in in vivo skin research.
  • 484
  • 08 Aug 2022
Topic Review
Mouse Models of Autism Spectrum Disorders
Autism spectrum disorder (ASD) is a neurodevelopmental condition with a prevalence rate of 2.78%, and it is characterized by deficits in sociability and communication and restricted patterns of interests and activities. Remarkably, this psychiatric disorder exhibits a pronounced gender bias, with 80% of children diagnosed with ASD being boys.
  • 484
  • 03 Aug 2023
Topic Review
Cholinergic Regulation of Hippocampal Theta Rhythm
Cholinergic regulation of hippocampal theta rhythm has been proposed as one of the central mechanisms underlying hippocampal functions including spatial memory encoding. However, cholinergic transmission has been traditionally associated with atropine-sensitive type II hippocampal theta oscillations that occur during alert immobility or in urethane-anesthetized animals. The role of cholinergic regulation of type I theta oscillations in behaving animals is much less clear. Recent studies strongly suggest that both cholinergic muscarinic and nicotinic receptors do actively regulate type I hippocampal theta oscillations and thus provide the cholinergic mechanism for theta-associated hippocampal learning. Septal cholinergic activation can regulate hippocampal circuit and theta expression either through direct septohippocampal cholinergic projections, or through septal glutamatergic and GABAergic neurons, that can precisely entrain hippocampal theta rhythmicity. 
  • 481
  • 06 Apr 2022
Topic Review
Neuromuscular Activity during Cycling Performance
To determine the relationships between limiting factors and neuromuscular activity during a self-paced 20-km cycling time trial and evaluate the effect of environmental conditions on fatigue indices. Methods: Ten endurance-trained and heat-acclimated athletes performed in three conditions (ambient temperature, relative humidity): HUMID (30 °C, 90%), DRY (35 °C, 46%) and NEUTRAL (22 °C, 55%). Voluntary muscular contractions and electromagnetic stimulations were recorded before and after the time trials to assess fatigue. The data on performance, temperature, heat storage, electromyogram, heart rate and rating of perceived exertion data were analyzed. Results: Performance was impaired in DRY and HUMID compared with NEUTRAL environment (p < 0.05). The force developed by the vastus lateral muscle during stimulation of the femoral nerve remained unchanged across conditions. The percentage of integrated electromyogram activity, normalized by the value attained during the pre-trial maximal voluntary contraction, decreased significantly throughout the trial only in HUMID condition (p < 0.01). Neuromuscular activity in peripheral skeletal muscle started to fall from the 11th km in HUMID and the 15th km in DRY condition, although core temperature did not reach critical values. Conclusions: These alterations suggest that afferences from core/skin temperature regulate the central neural motor drive, reducing the active muscle recruited during prolonged exercise in the heat in order to prevent the system from hyperthermia. 
  • 479
  • 29 Mar 2022
Topic Review
Mechanisms of Atrial Fibrillation
Atrial fibrillation (AF) is a very common arrhythmia that mainly affects older individuals. The mechanism of atrial fibrillation is complex and is related to the pathogenesis of trigger activation and the perpetuation of arrhythmia. The pulmonary veins in the left atrium arei confirm that onfirm the most common triggers due to their distinct anatomical and electrophysiological properties.
  • 478
  • 12 Jun 2023
Topic Review
Pathophysiological Implications of Interstitial Cajal-like Cells in Uterus
The main function of interstitial cells of Cajal (ICCs) is to regulate gastrointestinal peristalsis by acting as a “pacemaker” cell by generating spontaneous slow electrical waves. In 2005, electron microscopy revealed a cell type similar to ICCs (ICC-like) outside the gastrointestinal tract, with contractile activity and c-Kit+ immunohistochemistry shared with ICCs. Among the locations where ICC-like cells have been observed, it is in the uterus where they have a significant functional and pathophysiological role. These cells are involved in obstetric phenomena of contractile action, such as ascending sperm transport, embryo implantation, pregnancy, delivery, and the expulsion of menstrual debris. 
  • 477
  • 22 Sep 2023
Topic Review
The Gut Microbiota Function
The microbiota is known as the set of microorganisms residing in each ecosystem, with a symbiotic relationship and with adaptive properties and rapid renewal, forming a large metabolic unit. The intestinal microbiota is a set of microorganisms made up of approximately 100,000 million bacteria that live in people intestine. The microbiota is responsible, among other functions, for maintaining the well-being of the intestinal mucosa, helping digest food and converting harmful elements into less toxic substances.
  • 475
  • 17 Oct 2022
Topic Review
Role of Melatonin in Directing Plant Physiology
Melatonin (MT), a naturally occurring compound, is found in various species worldwide. In 1958, it was first identified in the pineal gland of dairy cows. MT is an “old friend” but a “new compound” for plant biology. It brings experts and research minds from the broad field of plant sciences due to its considerable influence on plant systems. The MT production process in plants and animals is distinct, where it has been expressed explicitly in chloroplasts and mitochondria in plants. Tryptophan acts as the precursor for the formation of phyto-melatonin, along with intermediates including tryptamine, serotonin, N-acetyl serotonin, and 5-methoxy tryptamine. It plays a vital role in growth phases such as the seed germination and seedling growth of crop plants. MT significantly impacts the gas exchange, thereby improving physio-chemical functions in plant systems. During stress, the excessive generation and accumulation of reactive oxygen species (ROS) causes protein oxidation, lipid peroxidation, nucleic acid damage, and enzyme inhibition. Because it directly acts as an antioxidant compound, it awakens the plant antioxidant defense system during stress and reduces the production of ROS, which results in decreasing cellular oxidative damage. MT can enhance plant growth and development in response to various abiotic stresses such as drought, salinity, high temperature, flooding, and heavy metals by regulating the antioxidant mechanism of plants.
  • 474
  • 17 Oct 2023
Topic Review
Calcium’s Role and Signaling in Muscle Aging
Calcium signaling involves the movement of calcium ions within or between cells, which can affect the electrochemical gradients between intra- and extracellular membranes, ligand binding, enzyme activity, and other mechanisms that determine cell fate. Calcium signaling in muscle, as elucidated by the sliding filament model, plays a significant role in muscle contraction. However, as organisms age, alterations occur within muscle tissue. These changes include sarcopenia, loss of neuromuscular junctions, and changes in mineral concentration, all of which have implications for calcium’s role. Additionally, a field of study that has gained recent attention, cellular senescence, is associated with aging and disturbed calcium homeostasis, and is thought to affect sarcopenia progression. 
  • 474
  • 06 Dec 2023
Topic Review
The Molecular Basis for Zinc Bioavailability
As an essential micronutrient with a nearly ubiquitous presence in nature, zinc is needed for all known aspects of life. Based on the quantification of putative zinc protein binding domains, it is estimated that one-tenth of all human proteins require zinc as a structural element or for an enzyme active site. The structural, catalytic, and regulatory roles of zinc provide the foundation for a broad array of basic cellular functions. Consequently, zinc deficiency affects numerous critical functions, including metabolic, immune, and neurological processes. With zinc nutriture underlying a public health burden of communicable and non-communicable diseases, human zinc deficiency is estimated to be the most prevalent nutrient deficiency worldwide. The etiology of human zinc deficiency has historically been attributed to diets with low zinc bioavailability, e.g., the proportion of dietary zinc available for zinc-dependent functions, with primary attention to diets low in zinc and high in phytic acid.
  • 473
  • 10 Apr 2023
Topic Review
Renal Sodium
Sodium retention is a well-documented consequence of many pathophysiological conditions, especially kidney disease, which is clinically recognized as an accumulation of edema.
  • 472
  • 14 Mar 2022
Topic Review
Decreased Trabecular Bone Mass in Col22a1-Deficient Mice
The bone matrix is constantly remodeled by the coordinated activities of bone-forming osteoblasts and bone-resorbing osteoclasts. Whereas type I collagen is the most abundant bone matrix protein, there are several other proteins present, some of them specifically produced by osteoblasts. In a genome-wide expression screening for osteoblast differentiation markers we have previously identified two collagen-encoding genes with unknown function in bone remodeling. Here we show that one of them, Col22a1, is predominantly expressed in bone, cultured osteoblasts, but not in osteoclasts. Based on this specific expression pattern we generated a Col22a1-deficient mouse model, which was analyzed for skeletal defects by µCT, undecalcified histology and bone-specific histomorphometry. We observed that Col22a1-deficient mice display trabecular osteopenia, accompanied by significantly increased osteoclast numbers per bone surface. In contrast, cortical bone parameters, osteoblastogenesis or bone formation were unaffected by the absence of Col22a1. Likewise, primary osteoblasts from Col22a1-deficient mice did not display a cell-autonomous defect, and they did not show altered expression of Rankl or Opg, two key regulators of osteoclastogenesis. Taken together, we provide the first evidence for a physiological function of Col22a1 in bone remodeling, although the molecular mechanisms explaining the indirect influence of Col22a1 deficiency on osteoclasts remain to be identified. 
  • 471
  • 11 Nov 2021
Topic Review
mTORC1 and Nutritional Interventions in Ageing
The effect of mTOR complex 1 (mTORC1) inhibitors in ageing has been a matter of scientific study since the 1990s. In fact, most initial efforts elucidating the beneficial effects of rapamycin have revealed its role in ageing, with Romero et al. describing in 1995 its effect in preventing reduced bone growth in aged rat. Since mTORC1 responds to nutritional availability, the effects of mTORC1 inhibition using specific inhibitors such as rapamycin or through nutritional interventions in ageing and health have been widely reviewed.
  • 471
  • 30 Sep 2022
Topic Review
Aging and Nicotinamide Adenine Dinucleotide Deficiency
Under normal physiological conditions, nicotinamide adenine dinucleotide (NAD+) consumption is matched by its synthesis primarily via the salvage pathway catalyzed by nicotinamide phosphoribosyltransferase (NAMPT). However, aging and muscular contraction enhance NAD+ utilization, whereas NAD+ replenishment is limited by cellular sources of NAD+ precursors and/or enzyme expression.
  • 471
  • 18 Apr 2022
Topic Review
Nrf2 in the Heart versus Other Systems
Nuclear factor erythroid 2-related factor 2 (Nrf2) is a master regulator of the endogenous antioxidant response to reactive oxygen species as well as a controller of Phase II detoxification in response to xenobiotics. However, more is not necessarily better as the heart's unique biochemical and molecular composition make it susceptible to damage if the Nrf2 response is uncontrolled.
  • 469
  • 15 Dec 2022
Topic Review
Beta-Amyloid Instigates Dysfunction of Mitochondria in Cardiac Cells
Alzheimer’s disease (AD) includes the formation of extracellular deposits comprising aggregated β-amyloid (Aβ) fibers associated with oxidative stress, inflammation, mitochondrial abnormalities, and neuronal loss. There is an associative link between AD and cardiac diseases; however, the mechanisms underlying the potential role of AD, particularly Aβ in cardiac cells, remain unknown. Here, we investigated the role of mitochondria in mediating the effects of Aβ1-40 and Aβ1-42 in cultured cardiomyocytes and primary coronary endothelial cells. Our results demonstrated that Aβ1-40 and Aβ1-42 are differently accumulated in cardiomyocytes and coronary endothelial cells. Aβ1-42 had more adverse effects than Aβ1-40 on cell viability and mitochondrial function in both types of cells. Mitochondrial and cellular ROS were significantly increased, whereas mitochondrial membrane potential and calcium retention capacity decreased in both types of cells in response to Aβ1-42. Mitochondrial dysfunction induced by Aβ was associated with apoptosis of the cells. The effects of Aβ1-42 on mitochondria and cell death were more evident in coronary endothelial cells. In addition, Aβ1-40 and Aβ1-42 significantly increased Ca2+ -induced swelling in mitochondria isolated from the intact rat hearts. In conclusion, this study demonstrates the toxic effects of Aβ on cell survival and mitochondria function in cardiac cells. 
  • 462
  • 09 Feb 2022
Topic Review
Physiological Functions of Melatonin in Horticultural Plants
Melatonin, a hormone known for its role in regulating sleep–wake cycles in mammals, has been found to have diverse functions in horticultural plants. Research has revealed the involvement of melatonin in various physiological processes in plants, like regulation of growth and development, stress tolerance, and antioxidant defense. Melatonin can augment seed germination, roots, shoot growth, and biomass accumulation in horticultural crops. It also performs a vital role in regulating vegetative and reproductive growth stages, floral transition, and leaf senescence. Melatonin improves stress tolerance in crops by regulating root architecture, nutrient uptake, and ion transport.
  • 458
  • 20 Sep 2023
Topic Review
Ion Channels in GBM Cell Migration and Death
Ca2+-activated K+ channels of large- and intermediate-conductance (BK and IK, respectively) and the volume-regulated anion channel (VRAC), are the main K+ and Cl- channels highly-expressed in glioblastoma (GBM) cells, where they play an essential role in the control of cell volume and, in turn, migration, invasion, and apoptotic cell death, the three main features underlying GBM malignancy and lethality.
  • 457
  • 14 Dec 2023
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