A dendritikus sejtek szerepe az immunológiai szinapszis kialakításában, a T-limfociták homeosztázisának és aktiválásának szabályozásában = The role of dendritic cells in the formation of immunological synapses and in the regulation of T lymphocyte homeostasis and activation

A CD14+ monociták CD1a- és CD1a+ DS-ekké differenciálódnak, de a CD1a- és CD1a+ sejtek arányát a szérum lipoproteinek dózis függően befolyásolják. Kinetikai vizsgálatok igazolták, hogy az éretlen CD1a- DS-ek CD1a+ sejtekké differenciálódnak, ezt az átalakulást az aktiváció gátolja. A CD1a- és CD1a+ DS-ek hasonló migrációs, de eltérő internalizáló, citokin és kemokin termelő képességgel rendelkeznek. Mindkét DS altípus hatékony T-limfocita aktiváló képességgel rendelkezik, de nagy mennyiségű IFNγ citokin termelésére csak a CD1a+ DS-ek által aktivált T-sejtek képesek. A transzkripcionálisan aktív PPARγ nukleáris receptor és target génje, az apolipoprotein E lényegesen magasabb expressziót mutat a CD1a-, mint a CD1a+ sejtekben. A PPARγ-CD1a+ sejtek kialakulása és a CD1a expressziót regulálni képes szérum lipidek hatása azt igazolja, hogy a PPARγ kifejeződése és aktivációja fontos szerepet játszik az immunológiai tolerancia kialakításában és fenntartásában. Az interleukin-7 (IL-7) citokin elősegíti a nyugvó T-limfociták túlélését és limfopéniásokban a T sejt osztódást. Az emelkedett IL-7 szint HIV-fertőzött egyedekben a T-limfocitákon magas Fas receptor kifejeződéssel és a Fas-mediált apoptózissal szembeni fokozott érzékenységgel társul. Kimutattuk, hogy az IL-7 naiv és memória sejtekben a Fas expresszió fokozódását váltja ki, és fontos szerepe van a T-sejt egyensúly fenntartásában és HIV ferőzöttekben a Fas-mediált apoptosis kiváltásában. | We have shown that CD14+ monocytes differentiate to both CD1a- and CD1a+ DC but the ratio of CD1a- and CD1a+ cells is modulated by serum lipoproteins in a dose dependent manner. Kinetic studies revealed that immature CD1a- DC differentiate to CD1a+ cells, but activation signals permanently block this process. The co-existing CD1a+ and CD1a- DC have similar migratory potential but differ in their internalizing capacity, cytokine and chemokine profiles. Although both moDC subtypes were potent inducers of T-lymphocyte proliferation, high production of IFNγ by inflammatory T-cells was induced preferentially by CD1a+ cells pointing to functional differences of these subsets. High expression of transcriptionally active PPARγ and their target gene apolipoprotein E in CD1a- cells compared to PPARγ-CD1a+ cells together with the regulatory potential of serum lipids on CD1a expression suggested lipid-mediated tolerance induction acting through PPARγ. Interleukin-7 (IL-7) promotes survival of resting T-lymphocytes and induces T cell proliferation in lymphopenic conditions. Elevated IL-7 levels in HIV-infected individuals accompanied with high Fas expression on T-cells induces increased sensitivity to Fas-mediated apoptosis. We have shown that IL-7 upregulates Fas expression on naïve and memory T-cells demonstrating an important role of IL-7 in the regulation of T-cell homeostasis and in Fas-mediated apoptosis in HIV-infected individuals

Psychedelic N,N-dimethyltryptamine and 5-methoxy-N,N-dimethyltryptamine modulate innate and adaptive inflammatory responses through the sigma-1 receptor of human monocyte-derived dendritic cells.

The orphan receptor sigma-1 (sigmar-1) is a transmembrane chaperone protein expressed in both the central nervous system and in immune cells. It has been shown to regulate neuronal differentiation and cell survival, and mediates anti-inflammatory responses and immunosuppression in murine in vivo models. Since the details of these findings have not been elucidated so far, we studied the effects of the endogenous sigmar-1 ligands N,N-dimethyltryptamine (NN-DMT), its derivative 5-methoxy-N,N-dimethyltryptamine (5-MeO-DMT) and the synthetic high affinity sigmar-1 agonist PRE-084 hydrochloride on human primary monocyte-derived dendritic cell (moDCs) activation provoked by LPS, polyI:C or pathogen-derived stimuli to induce inflammatory responses. Co-treatment of moDC with these activators and sigma-1 receptor ligands inhibited the production of pro-inflammatory cytokines IL-1β, IL-6, TNFα and the chemokine IL-8, while increased the secretion of the anti-inflammatory cytokine IL-10. The T-cell activating capacity of moDCs was also inhibited, and dimethyltryptamines used in combination with E. coli or influenza virus as stimulators decreased the differentiation of moDC-induced Th1 and Th17 inflammatory effector T-cells in a sigmar-1 specific manner as confirmed by gene silencing. Here we demonstrate for the first time the immunomodulatory potential of NN-DMT and 5-MeO-DMT on human moDC functions via sigmar-1 that could be harnessed for the pharmacological treatment of autoimmune diseases and chronic inflammatory conditions of the CNS or peripheral tissues. Our findings also point out a new biological role for dimethyltryptamines, which may act as systemic endogenous regulators of inflammation and immune homeostasis through the sigma-1 receptor

The Endogenous Hallucinogen and Trace Amine N,N-Dimethyltryptamine (DMT) Displays Potent Protective Effects against Hypoxia via Sigma-1 Receptor Activation in Human Primary iPSC-Derived Cortical Neurons and Microglia-Like Immune Cells

N,N-dimethyltryptamine (DMT) is a potent endogenous hallucinogen present in the brain of humans and other mammals. Despite extensive research, its physiological role remains largely unknown. Recently, DMT has been found to activate the sigma-1 receptor (Sig-1R), an intracellular chaperone fulfilling an interface role between the endoplasmic reticulum (ER) and mitochondria. It ensures the correct transmission of ER stress into the nucleus resulting in the enhanced production of antistress and antioxidant proteins. Due to this function, the activation of Sig-1R can mitigate the outcome of hypoxia or oxidative stress. In this paper, we aimed to test the hypothesis that DMT plays a neuroprotective role in the brain by activating the Sig-1R. We tested whether DMT can mitigate hypoxic stress in in vitro cultured human cortical neurons (derived from induced pluripotent stem cells, iPSCs), monocyte-derived macrophages (moMACs), and dendritic cells (moDCs). Results showed that DMT robustly increases the survival of these cell types in severe hypoxia (0.5% O2) through the Sig-1R. Furthermore, this phenomenon is associated with the decreased expression and function of the alpha subunit of the hypoxia-inducible factor 1 (HIF-1) suggesting that DMT-mediated Sig-1R activation may alleviate hypoxia-induced cellular stress and increase survival in a HIF-1-independent manner. Our results reveal a novel and important role of DMT in human cellular physiology. We postulate that this compound may be endogenously generated in situations of stress, ameliorating the adverse effects of hypoxic/ischemic insult to the brain

The endogenous hallucinogen and trace amine N,N-dimethyltryptamine (DMT) displays potent protective effects against hypoxia via sigma-1 receptor activation in human primary iPSC-derived cortical neurons and microglia-like immune cells

N,N-dimethyltryptamine (DMT) is a potent endogenous hallucinogen present in the brain of humans and other mammals. Despite extensive research, its physiological role remains largely unknown. Recently, DMT has been found to activate the sigma-1 receptor (Sig-1R), an intracellular chaperone fulfilling an interface role between the endoplasmic reticulum (ER) and mitochondria. It ensures the correct transmission of ER stress into the nucleus resulting in the enhanced production of antistress and antioxidant proteins. Due to this function, the activation of Sig-1R can mitigate the outcome of hypoxia or oxidative stress. In this paper, we aimed to test the hypothesis that DMT plays a neuroprotective role in the brain by activating the Sig-1R. We tested whether DMT can mitigate hypoxic stress in in vitro cultured human cortical neurons (derived from induced pluripotent stem cells, iPSCs), monocyte-derived macrophages (moMACs), and dendritic cells (moDCs). Results showed that DMT robustly increases the survival of these cell types in severe hypoxia (0.5% O2) through the Sig-1R. Furthermore, this phenomenon is associated with the decreased expression and function of the alpha subunit of the hypoxia-inducible factor 1 (HIF-1) suggesting that DMT-mediated Sig-1R activation may alleviate hypoxia-induced cellular stress and increase survival in a HIF-1-independent manner. Our results reveal a novel and important role of DMT in human cellular physiology. We postulate that this compound may be endogenously generated in situations of stress, ameliorating the adverse effects of hypoxic/ischemic insult to the brain.publishedVersio

RNA-DNA hybrid (R-loop) immunoprecipitation mapping: an analytical workflow to evaluate inherent biases

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