Biochemical and biological characterization of the Hypanus americanus mucus: A perspective on stingray immunity and toxins.

Stingrays skin secretions are largely studied due to the human envenoming medical relevance of the sting puncture that evolves to inflammatory events, including necrosis. Such toxic effects can be correlated to the biochemical composition of the sting mucus, according to the literature. Fish skin plays important biological roles, such as the control of the osmotic pressure gradient, protection against mechanical forces and microorganism infections. The mucus, on the other hand, is a rich and complex fluid, acting on swimming, nutrition and the innate immune system. The elasmobranch's epidermis is a tissue composed mainly by mucus secretory cells, and marine stingrays have already been described to present secretory glands spread throughout the body. Little is known about the biochemical composition of the stingray mucus, but recent studies have corroborated the importance of mucus in the envenomation process. Aiming to assess the mucus composition, a new non-invasive mucus collection method was developed that focused on peptides and proteins, and biological assays were performed to analyze the toxic and immune activities of the Hypanus americanus mucus. Pathophysiological characterization showed the presence of peptidases on the mucus, as well as the induction of edema and leukocyte recruitment in mice. The fractionated mucus improved phagocytosis on macrophages and showed antimicrobial activity against T. rubrumç. neoformans and C. albicans in vitro. The proteomic analyses showed the presence of immune-related proteins like actin, histones, hemoglobin, and ribosomal proteins. This protein pattern is similar to those reported for other fish mucus and stingray venoms. This is the first report depicting the Hypanus stingray mucus composition, highlighting its biochemical composition and importance for the stingray immune system and the possible role on the envenomation process.

Advanced cell therapy with low tissue factor loaded product NestaCell® does not confer thrombogenic risk for critically ill COVID-19 heparin-treated patients.

Since the COVID-19 pandemic started, mesenchymal stromal cells (MSC) appeared as a therapeutic option to reduce the over-activated inflammatory response and promote recovery of lung damage. Most clinical studies use intravenous injection for MSC delivery, raising several concerns of thrombogenic risk due to MSC procoagulant activity (PCA) linked to the expression of tissue factor (TF/CD142). This is the first study that demonstrated procoagulant activity of TF+ human immature dental pulp stromal cells (hIDPSC, NestaCell® product) with the percentage of TF+ cells varied from 0.2% to 63.9% in plasma of healthy donors and COVID-19 heparin-treated patients. Thrombogenic risk of TF+ hIDPSCs was evaluated by rotational thromboelastometry (in vitro) and in critically ill COVID-19 patients (clinical trial). We showed that the thromboelastography is not enough to predict the risk of TF+ MSC therapies. Using TF-negative HUVEC cells, we demonstrated that TF is not a unique factor responsible for the cell's procoagulant activity. However, heparin treatment minimizes MSC procoagulant (in vitro). We also showed that the intravenous infusion of hIDPSCs with prophylactic enoxaparin administration in moderate to critically ill COVID-19 patients did not change the values of D-dimer, neither in the PT and PTT times. Our COVID-19 clinical study measured and selected the therapeutic cells with low TF (less than 25% of TF+ hIDPSCs). Our data indicate that the concomitant administration of enoxaparin and low TF-loaded is safe even for critically ill COVID-19 patients.

Bothrops moojeni venom and its components - an overview.

Belonging to the Viperidae family, Bothrops moojeni are widely distributed in South America, tropical savanna ecoregion (Cerrado) of Argentina, Bolivia, Brazil, and Paraguay with medical importance in Brazil. Accidents caused by this species have a rapid local action with the development of tissue inflammation, causing erythema, pain, and increased clotting time, which can culminate in gangrene or tissue necrosis. Bothrops moojeni venom has a rich composition that remains underexplored, which is of utmost importance, both for elucidating the envenoming process and the vast library of new bioactive molecules kind of venom can offer. This review aims to analyze which components of the venom have already been characterized towards its structure and biological effect and highlight the pharmacological and biotechnological potential of this venom. Although snake venoms have been studied for their toxic effects for generations, innovative studies address their components as tools for discovering new therapeutic targets and new molecules with pharmacological and biotechnological potential.

Bothrops moojeni Venom and Its Components Strongly Affect Osteoclasts' Maturation and Protein Patterns.

Osteoclasts (OCs) are important for bone maintenance, calcium balance, and tissue regeneration regulation and are involved in different inflammatory diseases. Our study aimed to evaluate the effect of Bothrops moojeni's venom and its low and high molecular mass (HMM and LMM) fractions on human peripheral blood mononuclear cell (PBMC)-derived OCs' in vitro differentiation. Bothrops moojeni, a Brazilian lanced-head viper, presents a rich but not well-explored, venom composition. This venom is a potent inducer of inflammation, which can be used as a tool to investigate the inflammatory process. Human PBMCs were isolated and induced to OC differentiation following routine protocol. On the fourth day of differentiation, the venom was added at different concentrations (5, 0.5, and 0.05 µg/mL). We observed a significant reduction of TRAP+ (tartrate-resistant acid phosphatase) OCs at the concentration of 5 µg/mL. We evaluated the F-actin-rich OCs structure's integrity; disruption of its integrity reflects bone adsorption capacity. F-actin rings phalloidin staining demonstrated that venom provoked their disruption in treated OCs. HMM, fraction reduces TRAP+ OCs at a concentration of 5 µg/mL and LMM fraction at 1 µg/mL, respectively. Our results indicate morphological changes that the venom induced cause in OCs. We analyzed the pattern of soluble proteins found in the conditioned cell culture medium OCs treated with venom and its fractions using mass spectrometry (LC-MS/IT-Tof). The proteomic analyses indicate the possible pathways and molecular mechanisms involved in OC reduction after the treatment.

Exosomes in the Tumor Microenvironment: From Biology to Clinical Applications.

Cancer is one of the most important health problems and the second leading cause of death worldwide. Despite the advances in oncology, cancer heterogeneity remains challenging to therapeutics. This is because the exosome-mediated crosstalk between cancer and non-cancer cells within the tumor microenvironment (TME) contributes to the acquisition of all hallmarks of cancer and leads to the formation of cancer stem cells (CSCs), which exhibit resistance to a range of anticancer drugs. Thus, this review aims to summarize the role of TME-derived exosomes in cancer biology and explore the clinical potential of mesenchymal stem-cell-derived exosomes as a cancer treatment, discussing future prospects of cell-free therapy for cancer treatment and challenges to be overcome.

Stem Cell-Derived Exosomes as Therapeutic Approach for Neurodegenerative Disorders: From Biology to Biotechnology.

The aging population has contributed to the rapid rise in the global incidence of neurodegenerative diseases. Despite the medical advances, there are no effective treatments for these disorders. Therefore, there is an urgent need for new treatments for these diseases. In this sense, cell therapy has been recognized as the best candidate for treating incurable diseases, such as neurodegenerative disorders. However, the therapeutic use of these cells can be limited by several factors. Thus, there has been a rediscovery that extracellular vesicles, including exosomes, can be alternatively explored in the treatment of these diseases, overcoming the limits of cell-based therapy. In this sense, this review aims to revisit all areas from biology, including biogenesis and the content of exosomes, to biotechnology, proposing the minimal information required to isolate, characterize, and study the content of these vesicles for scientific and/or clinical purposes.