Topic Review
Phenylketonuria and Hereditary Tyrosinemia
Phenylalanine hydroxylase (PAH) and fumarylacetoacetate hydroxylase (FAH) are two highly regulated liver enzymes that catalyze the rate-limiting step in phenylalanine and tyrosine metabolism. Mammalian PAH (phenylalanine 4-monooxygenase, E.C. 1.14.16.1) catalyzes the stereospecific hydroxylation of L-phenylalanine into L-tyrosine using tetrahydrobiopterin (BH4), non-heme iron, and dioxygen as co-substrates in the cytosol of the liver and kidney. PAH facilitates oxidation of excess L-phenylalanine into carbon dioxide and water, and is the major enzyme degrading 75% of L-phenylalanine from the diet. PAH assembles as a homotetrameric protein, each subunit composed of N-terminal regulatory domain for allosteric activation by Phe, a central catalytic domain, and C-terminal helix responsible for tetramer formation.
  • 856
  • 27 Oct 2020
Topic Review
Alveologenesis
Alveologenesis is the final stage of lung maturation, when an alveolar region is divided into smaller units called alveoli via the process known as secondary septation. Each of the formed septa serves as a new gas exchange surface, and all together, they dramatically increase the respiratory surface area. Alveologenesis is divided into 2 phases: classical and continued. During the classical alveologenesis, the secondary septa are formed and the number of alveoli increases. During the continued alveologenesis, the maturation and thinning of the septa occur and the size of alveoli increases. The disruption of alveologenesis leads to the simplification of the alveoli, as seen in preterm infants diagnosed with bronchopulmonary dysplasia (BPD), a widespread pulmonary disease that is often connected with lifelong respiratory failure.
  • 854
  • 23 Nov 2021
Topic Review
Interactions of SARS-CoV-2 & Variants with Cellular Components
Given the global scale of the COVID-19 pandemic and the health emergency it has caused, it is crucial to understand the impact of SARS-CoV-2 and its mutations. Here, we comprehensively review SARS-CoV-2 interactions with host cells, describe SARS-CoV-2 variants, assess impact of their protein mutations and enumerate databases with SARS-CoV-2 host-pathogen interaction data. 
  • 854
  • 24 Nov 2021
Topic Review
HGPS and Cardiovascular Disease
Hutchinson-Gilford progeria syndrome (HGPS) is a rare genetic disease that recapitulates many symptoms of physiological aging and precipitates death. Patients develop severe vascular alterations, mainly massive vascular smooth muscle cell loss, vessel stiffening, calcification, fibrosis, and generalized atherosclerosis, as well as electrical, structural, and functional anomalies in the heart. As a result, most HGPS patients die of myocardial infarction, heart failure, or stroke typically during the first or second decade of life. No cure exists for HGPS, and therefore it is of the utmost importance to define the mechanisms that control disease progression in order to develop new treatments to improve the life quality of patients and extend their lifespan. Since the discovery of the HGPS-causing mutation, several animal models have been generated to study multiple aspects of the syndrome and to analyze the contribution of different cell types to the acquisition of the HGPS-associated cardiovascular phenotype.
  • 854
  • 22 Sep 2021
Topic Review
MSC-Based Therapy in Osteoarthritis Treatment
Osteoarthritis (OA) is a chronic degenerative disorder of the joint and its prevalence and severity is increasing owing to ageing of the population. Osteoarthritis is characterized by the degradation of articular cartilage and remodeling of the underlying bone. Extracellular vesicles are naturally released by cells and they carry their origin cell information to be delivered to target cells. On the other hand, mesenchymal stem cells (MSCs) are highly proliferative and have a great potential in cartilage regeneration. 
  • 851
  • 02 Jun 2021
Topic Review
Nrf2 and Oxidative Stress
Organisms are continually exposed to exogenous and endogenous sources of reactive oxygen species (ROS) and other oxidants that have both beneficial and deleterious effects on the cell. ROS have important roles in a wide range of physiological processes; however, high ROS levels are associated with oxidative stress and disease progression. Oxidative stress has been implicated in nearly all major human diseases, from neurogenerative diseases and neuropsychiatric disorders to cardiovascular disease, diabetes, and cancer. Antioxidant defence systems have evolved as a means of protection against oxidative stress, with the transcription factor Nrf2 as the key regulator.
  • 849
  • 01 Feb 2023
Topic Review
Antioxidant Therapy in Cancer
Cancer is characterized by increased oxidative stress, an imbalance between reactive oxygen species (ROS) and antioxidants. Enhanced ROS accumulation, as a result of metabolic disturbances and signaling aberrations, can promote carcinogenesis and malignant progression by inducing gene mutations and activating pro-oncogenic signaling, providing a possible rationale for targeting oxidative stress in cancer treatment.
  • 849
  • 29 Jul 2022
Topic Review
MicroRNA-7 (MiR-7) in Cancer Physiopathology
miRNAs are non-coding RNA sequences of approximately 22 nucleotides that interact with genes by inhibiting their translation through binding to their 3′ or 5′ UTR regions. Following their discovery, the role they play in the development of various pathologies, particularly cancer, has been studied. In this context, miR-7 is described as an important factor in the development of cancer because of its role as a tumor suppressor, regulating a large number of genes involved in the development and progression of cancer. Data support the function of miR-7 as a prognostic biomarker in cancer, and miR-7 has been proposed as a strategy in cancer therapy.
  • 848
  • 16 Aug 2022
Topic Review
Replicative Senescence in Different Types of Stem Cells
Stem cells serve as a source of cellular material in embryogenesis and postnatal growth and regeneration. This requires significant proliferative potential ensured by sufficient telomere length. Telomere attrition in the stem cells and their niche cells can result in the exhaustion of the regenerative potential of high-turnover organs, causing or contributing to the onset of age-related diseases. Telomerase activity is present in most types of adult stem cells, though at substantially lower levels. Such lower levels are sufficient for slowing down telomere shortening and expanding the replicative lifespan  but cannot prevent replicative senescence. In this case, low telomerase expression may provide protection against the malignant transformation of stem cells.
  • 848
  • 13 Oct 2022
Topic Review
Fluorescence Microscopy
Fluorescence microscopy has become a critical tool for researchers to understand biological processes at the cellular level. Micrographs from fixed and live-cell imaging procedures feature in a plethora of scientific articles for the field of cell biology.
  • 847
  • 10 Feb 2022
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