Amyloid-β (Aβ) deposition, a hallmark of Alzheimer’s disease, is known to induce free radical production and oxidative stress, leading to neuronal damage. During oxidative stress, several cell types (including astrocytes) can activate the nuclear factor erythroid 2-related factor 2 (Nrf2), a regulator of several phase II detoxifying and antioxidant genes, such as the System X_c⁻ subunit xCT. Here, we studied (i) the effect of the Aβ fragment 25-35 (Aβ_25-35) on Nrf2-dependent System X_c⁻ expression in U373 human astroglial cells and (ii) the effect of Aβ_25-35-induced astrocytic response on neuronal cell viability using an in vitro co-culture system. We found that Aβ_25-35 was able to activate an antioxidant response in astrocytes, by inducing both Nrf2 activation and System X_c⁻ up-regulation. However, this astrocytic response caused an enhanced cell mortality of co-cultured SH-SY5Y cells, taken as a neuronal model. Consistently, the specific System X_c⁻ inhibitor sulfasalazine prevented the increase of both neuronal mortality and extracellular glutamate levels, thus indicating that the neurotoxic effect was due to an augmented release of glutamate through the transporter. The involvement of NMDA receptor activation in this pathway was also demonstrated using the specific inhibitor MK801 that completely restored neuronal viability at the control levels. The present study sheds light on the Nrf2/system X_c⁻ pathway in the toxicity induced by Aβ_25-35 and may help to better understand the involvement of astrocytes in neuronal death during Alzheimer’s disease.

In the field of research for designing and preparing innovative nanostructured systems, these systems are able to reveal the presence of heavy metals in water samples, and can efficiently and selectively interact with them, allowing for future applications in the field of water remediation. We investigated the electronic and molecular structure, as well as the morphology, of silver nanoparticles stabilized by mixed biocompatible ligands (the amino acid L-cysteine and the organic molecule citrate) in the presence of cadmium and arsenic ions. The molecular, electronic, and local structure at the ligands/silver nanoparticles interface was probed by the complementary synchrotron radiation-induced techniques (SR-XPS, NEXAFS and XAS). The optical absorption (in the UV-Vis range) of the nanosystem was investigated in the presence of Cd(II) and As(III) and the observed behavior suggested a selective interaction with cadmium. In addition, the toxicological profile of the innovative nanosystem was assessed in vitro using a human epithelial cell line HEK293T. We analyzed the viability of the cells treated with silver nanoparticles, as well as the activation of antioxidant response.

The Trans-Activator of Transcription (Tat) of Human Immunodeficiency Virus (HIV-1) is involved in virus replication and infection and can promote oxidative stress in human astroglial cells. In response, host cells activate transcription of antioxidant genes, including a subunit of System X_c⁻ cystine/glutamate antiporter which, in turn, can trigger glutamate-mediated excitotoxicity. Here, we present data on the efficacy of bovine Lactoferrin (bLf), both in its native (Nat-bLf) and iron-saturated (Holo-bLf) forms, in counteracting oxidative stress in U373 human astroglial cells constitutively expressing the viral protein (U373-Tat). Our results show that, dependent on iron saturation, both Nat-bLf and Holo-bLf can boost host antioxidant response by up-regulating System X_c⁻ and the cell iron exporter Ferroportin via the Nuclear factor erythroid 2-related factor (Nrf2) pathway, thus reducing Reactive Oxygen Species (ROS)-mediated lipid peroxidation and DNA damage in astrocytes. In U373-Tat cells, both forms of bLf restore the physiological internalization of Transferrin (Tf) Receptor 1, the molecular gate for Tf-bound iron uptake. The involvement of astrocytic antioxidant response in Tat-mediated neurotoxicity was evaluated in co-cultures of U373-Tat with human neuronal SH-SY5Y cells. The results show that the Holo-bLf exacerbates Tat-induced excitotoxicity on SH-SY5Y, which is directly dependent on System-X_c⁻ upregulation, thus highlighting the mechanistic role of iron in the biological activities of the glycoprotein.

Transient receptor potential ankyrin 1 (TRPA1) channels detect noxious cold and inflammatory mediators in mammals; yet their evolutionary origins and roles in neuro-immune integration remain unclear. Here, we investigated TRPA1 in Hydra vulgaris, an early metazoan with a simple nervous system, exposing polyps to noxious cold and Pseudomonas aeruginosa lysate. Using Western blotting, pharmacological modulation, and gene expression analyses, we demonstrated that TRPA1 mediates upregulation of nociceptive markers (Nrf2, NOS, SOD) and immune effectors (NF-κB, NOS, periculin, hydramacin). TRPA1 antagonism significantly reduced these responses, indicating its role as an amplifier of both nociceptive and innate immune signaling. These findings suggest that TRPA1-dependent coupling of nociceptive-like and immune responses is an ancient, conserved mechanism, providing insights into the molecular basis of integrated threat detection and offering potential avenues for targeting pain and inflammation-associated pathologies.

Much evidence now indicates a direct crosstalk between thyroid hormones (THs) and the immune system. We previously showed that THs behave as anti-inflammatory agents in human leukemic THP-1 monocytes, but a potential neuroprotective effect of THs in microglia have been under-investigated. Microglia, the primary innate immune cells of the brain, play a pivotal role in the regulation of neuroinflammation and nongenomic integrin αvβ3-mediated action of THs appear to be involved. Integrin αvβ3 was highly expressed in activated BV-2 cells, while it was decreased by THs. In addition, THs facilitated wound healing in BV-2 murine microglia cells activated by lipopolysaccharide (LPS), through integrin αvβ3 and reactive oxygen species (ROS), with tetrac (a metabolite of TH) potentiated the inhibition of migration. Nitric oxide (NO) played a role with different mechanisms in the presence of either T3 or T4. Our data showed the capability of TH and analogues to modulate the M1-to-M2 microglial transition and suggest a new spectrum of actions in the central nervous system (CNS).

Organismal aging is not inevitable in multicellular animals, as early-branching metazoan lineages, such as cnidarians, display negligible senescence under defined conditions, despite conserved cellular pathways. Contrasting longevity phenotypes in Hydra species reveal distinct regulatory mechanisms underlying aging. A comparison between Hydra vulgaris and Hydra oligactis suggests that sustained telomerase activity, autophagy regulation, and microbiome stability in H. vulgaris are associated with stem cell renewal and long-term tissue homeostasis, whereas cold-induced stress in H. oligactis is accompanied by a disruption of these pathways, leading to rapid somatic decline, where autophagy dysfunction and microbiome dysbiosis may act as contributing or amplifying factors. Environmental sensing via conserved pathways may integrate these regulatory mechanisms. These observations suggest that aging in early-branching metazoans is a regulated, context-dependent process characterized by substantial lineage-specific variation rather than an inevitable, universal consequence of cellular senescence. Further mechanistic studies may provide evolutionary insights into longevity mechanisms and identify potential targets for modulating aging, although direct experimental validation remains necessary.