Plasticity of Adipose Tissue-Derived Stem Cells and Regulation of Angiogenesis

Adipose tissue is recognized as an important organ with metabolic, regulatory, and plastic roles. Adipose tissue-derived stem cells (ASCs) with self-renewal properties localize in the stromal vascular fraction (SVF) being present in a vascular niche, thereby, contributing to local regulation of angiogenesis and vessel remodeling. In the past decades, ASCs have attracted much attention from biologists and bioengineers, particularly, because of their multilineage differentiation potential, strong proliferation, and migration abilities in vitro and high resistance to oxidative stress and senescence. Current data suggest that the SVF serves as an important source of endothelial progenitors, endothelial cells, and pericytes, thereby, contributing to vessel remodeling and growth. In addition, ASCs demonstrate intriguing metabolic and interlineage plasticity, which makes them good candidates for creating regenerative therapeutic protocols, in vitro tissue models and microphysiological systems, and tissue-on-chip devices for diagnostic and regeneration-supporting purposes. This review covers recent achievements in understanding the metabolic activity within the SVF niches (lactate and NAD+ metabolism), which is critical for maintaining the pool of ASCs, and discloses their pro-angiogenic potential, particularly, in the complex therapy of cardiovascular and cerebrovascular diseases

Copy Number of Human Ribosomal Genes With Aging: Unchanged Mean, but Narrowed Range and Decreased Variance in Elderly Group

Introduction: The multi-copied genes coding for the human 18, 5.8, and 28S ribosomal RNA (rRNA) are located in five pairs of acrocentric chromosomes forming so-called rDNA. Human genome contains unmethylated, slightly methylated, and hypermethylated copies of rDNA. The major research question: What is the rDNA copy number (rDNA CN) and the content of hypermethylated rDNA as a function of age?Materials and Methods: We determined the rDNA CN in the blood leukocyte genomes of 651 subjects aged 17 to 91 years. The subjects were divided into two subgroups: “elderly” group (E-group, N = 126) – individuals over 72 years of age (the age of the population’s mean lifetime for Russia) and “non-elderly” group (NE-group, N = 525). The hypermethylated rDNA content was determined in the 40 DNA samples from the each group. The change in rDNA during replicative cell senescence was studied for the cultured skin fibroblast lines of five subjects from NE-group. Non-radioactive quantitative dot- and blot-hybridization techniques (NQH) were applied.Results: In the subjects from the E-group the mean rDNA CN was the same, but the range of variation was narrower compared to the NE-group: a range of 272 to 541 copies in E-group vs. 200 to 711 copies in NE-group. Unlike NE-group, the E-group genomes contained almost no hypermethylated rDNA copies. A case study of cultured skin fibroblasts from five subjects has shown that during the replicative senescence the genome lost hypermethylated rDNA copies only.Conclusion: In the elderly group, the mean rDNA CN is the same, but the range of variation is narrower compared with the younger subjects. During replicative senescence, the human fibroblast genome loses hypermethylated copies of rDNA. Two hypotheses were put forward: (1) individuals with either very low or very high rDNA content in their genomes do not survive till the age of the population’s mean lifetime; and/or (2) during the aging, the human genome eliminates hypermethylated copies of rDNA

Neuroinflammation and Infection: Molecular Mechanisms Associated with Dysfunction of Neurovascular Unit

Neuroinflammation is a complex inflammatory process in the central nervous system, which is sought to play an important defensive role against various pathogens, toxins or factors that induce neurodegeneration. The onset of neurodegenerative diseases and various microbial infections are counted as stimuli that can challenge the host immune system and trigger the development of neuroinflammation. The homeostatic nature of neuroinflammation is essential to maintain the neuroplasticity. Neuroinflammation is regulated by the activity of neuronal, glial, and endothelial cells within the neurovascular unit, which serves as a “platform” for the coordinated action of pro- and anti-inflammatory mechanisms. Production of inflammatory mediators (cytokines, chemokines, reactive oxygen species) by brain resident cells or cells migrating from the peripheral blood, results in the impairment of blood-brain barrier integrity, thereby further affecting the course of local inflammation. In this review, we analyzed the most recent data on the central nervous system inflammation and focused on major mechanisms of neurovascular unit dysfunction caused by neuroinflammation and infections

The Phosphonate Derivative of C60 Fullerene Induces Differentiation towards the Myogenic Lineage in Human Adipose-Derived Mesenchymal Stem Cells

Inductors of myogenic stem cell differentiation attract attention, as they can be used to treat myodystrophies and post-traumatic injuries. Functionalization of fullerenes makes it possible to obtain water-soluble derivatives with targeted biochemical activity. This study examined the effects of the phosphonate C60 fullerene derivatives on the expression of myogenic transcription factors and myogenic differentiation of human mesenchymal stem cells (MSCs). Uptake of the phosphonate C60 fullerene derivatives in human MSCs, intracellular ROS visualization, superoxide scavenging potential, and the expression of myogenic, adipogenic, and osteogenic differentiation genes were studied. The prolonged MSC incubation (within 7–14 days) with the C60 pentaphoshonate potassium salt promoted their differentiation towards the myogenic lineage. The transcription factors and gene expressions determining myogenic differentiation (MYOD1, MYOG, MYF5, and MRF4) increased, while the expression of osteogenic differentiation factors (BMP2, BMP4, RUNX2, SPP1, and OCN) and adipogenic differentiation factors (CEBPB, LPL, and AP2 (FABP4)) was reduced or did not change. The stimulation of autophagy may be one of the factors contributing to the increased expression of myogenic differentiation genes in MSCs. Autophagy may be caused by intracellular alkalosis and/or short-term intracellular oxidative stress

Современные методы и материалы моделирования тканей мозга и гематоэнцефалического барьера in vitro

Neurovascular unit (NVU) is an ensemble of brain cells (cerebral endothelial cells, astrocytes, pericytes, neurons, and microglia), which regulates processes of transport through the blood-brain barrier (BBB) and controls local microcirculation and intercellular metabolic coupling. Dysfunction of NVU contributes to numerous types of central nervous system pathology. NVU pathophysiology has been extensively studied in various animal models of brain disorders, and there is growing evidence that modern approaches utilizing in vitro models are very promising for the assessment of intercellular communications within the NVU. Development of NVU‑on-chip or BBB‑on-chip as well as 3D NVU and brain tissue models suggests novel clues to understanding cell-to-cell interactions critical for brain functional activity, being therefore very important for translational studies, drug discovery, and development of novel analytical platforms. One of the mechanisms controlled by NVU activity is neurogenesis in highly specialized areas of brain (neurogenic niches, NNs), which are well-equipped for the maintenance of stem/progenitor cell pool and proliferation, differentiation, and migration of newly formed neuronal and glial cells. Specific properties of brain microvascular endothelial cells, particularly, high content of mitochondria, are important for establishment of vascular support in NVU and NNs. Metabolic activity of cells within NNs and NVU contributes to maintaining intercellular communications critical for the multicellular module integrity. We will discuss modern approaches to development of optimal microenvironment for in vitro BBB, NVU and NN models with the special focus on neuroengineering and bioprinting potentialsНейроваскулярная единица (НВЕ) – это совокупность клеток головного мозга (церебральные эндотелиальные клетки, астроциты, перициты, нейроны, микроглия), которые регулируют процессы транспорта через гематоэнцефалический барьер (ГЭБ), контролируют местную микроциркуляцию, межклеточную метаболическую связь. Дисфункция НВЕ способствует возникновению многих типов патологии центральной нервной системы. Патофизиология НВЕ широко изучена на различных моделях заболеваний мозга на животных. В настоящее время появляется все больше свидетельств того, что современные подходы с использованием моделей in vitro наиболее перспективны для оценки межклеточных коммуникаций внутри НВЕ. Разработка сосудисто-нервных единиц на чипе или ГЭБ на чипе, а также 3D НВЕ и модели ткани мозга обеспечивают новые подходы к пониманию межклеточных взаимодействий, критических для функциональной активности мозга, поэтому они очень важны для трансляционных исследований, открытия лекарств и создания новых аналитических платформ. Одним из механизмов, который контролируется активностью НВЕ, является нейрогенез в узкоспециализированных областях мозга (нейрогенные ниши, НН), которые служат источником для поддержания пула стволовых/ прогениторных клеток, пролиферации, дифференциации и миграции новообразованных нейронов и глиальных клеток. Специфические свойства эндотелиальных клеток микрососудов головного мозга, в частности высокое содержание митохондрий, важны для создания сосудистой поддержки при НВЕ и НН. Метаболическая активность клеток внутри НН и НВЕ способствует поддержанию межклеточных коммуникаций, критически важных для целостности многоклеточного модуля. В работе обсуждаются современные подходы к разработке оптимальной микросреды для in vitro моделей ГЭБ, НВЕ и НН. Особое внимание уделено перспективам нейроинженерии и биопечат

Une âme de jeune fille [ : Gabrielle***] / Jean Vaudon,...

<p>A. Distribution of CpG-motifs within rDNA (transcribed region of human ribosomal repeat). The digits indicate the nucleotide order number, the vertical bar shows the motif location. Red color is used to mark region A and region B, that were analyzed for the presence of methylated CCGG sites. B. Determination of methylation index of three genes in DNA from cells treated with 20 μM DBP(1–4), 72 h (description is given in Methods).</p