Human adipose-derived stem cells (ASCs), despite being one of the most attractive cell populations for tissue engineering and regenerative medicine, currently have certain limitations that reduce their therapeutic efficacy. One of the most serious problems is the poor engraftment of cryopreserved ASCs at injured tissue, attributed to the diminished biological activity of ASCs immediately post-thaw and their poor survival under harsh conditions of oxidative stress. Seeking to address these issues, we have developed a hormetic strategy to preadapt human ASCs to oxidative stress based on a new hydrogen peroxide preconditioning procedure, resulting in cells we call HC016. These cells rapidly recover their biological activity and functionality after cryopreservation while maintaining their mesenchymal stem cell status. Compared with non-preconditioned ASCs, HC016 cells showed (a) faster in vitro adhesion capacity and cell cycle progression immediately post-thaw, (b) enhanced cell survival under oxidative stress in a serum-free environment, and (c) heightened chemotaxis towards damage signals of oxidized glial cells. In addition, compared with ASCconditioned medium, HC016-conditioned medium showed a greater cytoprotective and pro-recovery effect on oxidized fibroblasts under serum-free conditions. Consistent with these results, in HC016 cells exposed to oxidative stress, we observed markedly higher expression of insulin-like growth factor-1 (a key factor in cell survival and migration) and of 6-phosphofructo-2-kinase/fructose-2,6-biphosphatase 4 and pyruvate dehydrogenase kinase isozyme 1 (essential enzymes to upregulate glycolysis and downregulate oxidative phosphorylation) along with lower basal mitochondrial activity. Taking into account all the aforementioned advantages, HC016 cells might be considered an important breakthrough in ASC-based cell therapies.

Designing degradable hydrogels is complicated by the structural and temporal complexities of the gel and evolving tissue. A major challenge is to create scaffolds with sufficient mechanical properties to restore initial function while simultaneously controlling temporal changes in the gel structure to facilitate tissue formation. Poly(ethylene glycol) was used in this work, to form biodegradable poly(ethylene glycol)-based hydrogels with hydrolyzable poly-l-lactide segments in the backbone. Non-degradable poly(ethylene glycol) was also introduced in the formulation to obtain control of the degradation profile that encompasses cell growth and new tissue formation. The dependence on polymer composition was observed by higher degradation profiles and decreased mechanical properties as the content of degradable segments was increased in the formulation. Based on in vitro tests, no toxicity of extracts or biomaterial in direct contact with human adipose tissue stem cells was observed, and the ultraviolet light treatment did not affect the proliferation capacity of the cells.

The COVID-19 pandemic caused by SARS-CoV-2 has reached 5.5 million deaths worldwide, generating a huge impact globally. This highly contagious viral infection produces a severe acute respiratory syndrome that includes cough, mucus, fever and pneumonia. Likewise, many hospitalized patients develop severe pneumonia associated with acute respiratory distress syndrome (ARDS), along an exacerbated and uncontrolled systemic inflammation that in some cases induces a fatal cytokine storm. Although vaccines clearly have had a beneficial effect, there is still a high percentage of unprotected patients that develop the pathology, due to an ineffective immune response. Therefore, a thorough understanding of the modulatory mechanisms that regulate the response to SARS-CoV-2 is crucial to find effective therapeutic alternatives. Previous studies describe the relevance of Neddylation in the activation of the immune system and its implications in viral infection. In this context, the present study postulates Neddylation, a reversible ubiquitin-like post-translational modification of proteins that control their stability, localization and activity, as a key regulator in the immune response against SARS-CoV-2. For the first time, we describe an increase in global neddylation levels in COVID-19 in the serum of patients, which is particularly associated with the early response to infection. In addition, the results showed that overactivation of neddylation controls activation, proliferation, and response of peripheral blood mononuclear cells (PBMCs) isolated from COVID-19 patients. Inhibition of neddylation, and the subsequent avoidance of activated PBMCs, reduces cytokine production, mainly IL-6 and MCP-1 and induce proteome modulation, being a critical mechanism and a potential approach to immunomodulate COVID-19 patients.

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