A stresszválasz hipotalamikus szabályozása = Hypothalamic regulation of the stress response

Vizsgálatainkban funkcionális neuroanatómiai és molekuláris biológiai technikák kombinációjával vizsgáltuk különböző stresszorok hatását a hipotalamusz paraventrikuláris magjának (PVN) a neuroendokrin és a vegetativ szabályozásban szerepet játszó neuroncsoportjaira. Elektronmikroszkópos technikákkal kimutattuk, hogy a neuroendokrin stresszválasz elindításáért felelős kortikotropin-releasing hormont (CRH) termelő idegsejteken GABAerg axonok végződnek és ezek száma, elhelyezkedési mintázata változik krónikus stresszben. A CRH neuronok szomszédságában hisztaminerg axonokat is feltérképeztünk, de ezek nem képeznek szinaptikus kapcsolatot a stresszel kapcsolatos hipotalamikus neuronokkal. A hisztamin hiány hisztidin dekarboxylase génkiütött egerek (HDC-KO) esetében nem okoz eltérést sem a stressz-, sem az anyagcsere szabályozásában szereplő hipotalamikus neuropeptidek expressziójában, mégis az állatokon olyan metabolikus fenotípus alakul ki, melynek jellemzői az elhízás, a glükóz intolerancia és a hiperleptinémia. Leírtuk, hogy a GABAerg gátló tónus felfüggesztése, valamint fizikális-, metabolikus- és immunstresszorok eltérő módon aktiválják a paraventrikuláris mag funkcionálisan különböző neuroncsoportjait és a CRH valamint az arginin vazopresszin (AVP) gének időben és térben eltérő indukcióját eredményezik a PVN-ben. Organotipikus hipotalamusz szelet tenyészeteken igazoltuk, hogy a szteroidok CRH expressziót gátló hatása közvetlenül a parvocelluláris neuronokon érvényesül | The effect of different stress challenges on the functionally distinct cell population in the hypothalamic paraventricular nucleus (PVN) has been studied by combination of anatomical and molecular biological methods. GABAergic terminals have been revealed on the corticotropin-releasing hormone (CRH) synthesizing neurons. The number and spatial distribution of these terminals has been changed after chronic stress. Histaminergic boutons have been identified in close apposition to CRH neurons without any synaptic contact. Lack of histamine in histidine decarboxylase knockout (HDC-KO) mice results in a metabolic phenotype with visceral obesity, glucose intolerance and hiperleptinemia without any detectable changes in the expression of neuropeptides involved in stress or metabolic regulation. We have revealed that suspension of inhibitory GABAergic tone, as well as physical, immune and metabolic challenges differentially recruit functionally distinct domains of the PVN and result in spatially and temporally different upregulation pattern of CRH and AVP genes. Using organotypic hypothalamic slice cultures we have provided evidence for the direct inhibitory effect of corticosteroid hormones on the CRH gene expression in the parvocellular neurons

Immunomodulatory and potential therapeutic role of mesenchymal stem cells in periodontitis

Periodontitis is a chronic inflammatory disease leading to alveolar bone destruction, and eventually tooth loss. In genetically or environmentally predisposed individuals periodontopathogenic bacteria trigger an inflammatory immune response where activated macrophages secrete inflammatory cytokines and T helper 17 cells produce interleukin-17, receptor activator of nuclear factor kappa B ligand (RANKL) and tumor necrosis factor-alpha. Inflammation and the production of RANKL, the key cytokine responsible for osteoclast activation, cause excessive activation of osteoclasts. This results in a decoupling between bone formation and resorption, leading to bone loss. As conventional treatment does not target the inflammatory response and osteoclast activation, its effectiveness is limited. Novel treatments are thus required if we are to cure this disease. Mesenchymal stem cells (MSCs), including those of dental origin, are potent immunomodulators and are known to be suitable for tissue regeneration. MSCs can inhibit the immune response by suppressing T cells, inducing regulatory T cells and converting dendritic cells and macrophages into a regulatory phenotype. Additionally, genetic modulation may enhance the therapeutic potential of MSCs. In the present review the authors describe the potential use of MSCs, either unmodified or engineered for therapeutic purposes in periodontitis, with special emphasis on MSCs from dental pulp and periodontal ligament. The paper envisions that multiple targeting of this inflammatory disease by modulating the immune response, promoting bone regeneration and inhibiting bone resorption might yield significantly improved treatment outcomes when combined with conventional treatment modalities

SARS-CoV-2 infection in cardiovascular disease: Unmet need of stem cell models

This review aims to summarise new approaches in SARS-CoV-2-related research in cardiology. We provide a head-to-head comparison of models, such as animal research and human pluripotent stem cells, to investigate the pathomechanisms of COVID-19 and find an efficient therapy. In vivo methods were useful for studying systemic processes of the disease; however, due to differences in animal and human biology, the clinical translation of the results remains a complex task. In vitro stem cell research makes cellular events more observable and effective for finding new drugs and therapies for COVID-19, including the use of stem cells. Furthermore, multicellular 3D organoids even make it possible to observe the effects of drugs to treat SARS-CoV-2 infection in human organ models

Culturing and Scaling up Stem Cells of Dental Pulp Origin Using Microcarriers

Ectomesenchymal stem cells derived from the dental pulp are of neural crest origin, and as such are promising sources for cell therapy and tissue engineering. For safe upscaling of these cells, microcarrier-based culturing under dynamic conditions is a promising technology. We tested the suitability of two microcarriers, non-porous Cytodex 1 and porous Cytopore 2, for culturing well characterized dental pulp stem cells (DPSCs) using a shake flask system. Human DPSCs were cultured on these microcarriers in 96-well plates, and further expanded in shake flasks for upscaling experiments. Cell viability was measured using the alamarBlue assay, while cell morphology was observed by conventional and two-photon microscopies. Glucose consumption of cells was detected by the glucose oxidase/Clark-electrode method. DPSCs adhered to and grew well on both microcarrier surfaces and were also found in the pores of the Cytopore 2. Cells grown in tissue culture plates (static, non-shaking conditions) yielded 7 × 105 cells/well. In shake flasks, static preincubation promoted cell adhesion to the microcarriers. Under dynamic culture conditions (shaking) 3 × 107 cells were obtained in shake flasks. The DPSCs exhausted their glucose supply from the medium by day seven even with partial batch-feeding. In conclusion, both non-porous and porous microcarriers are suitable for upscaling ectomesenchymal DPSCs under dynamic culture conditions