Mesenchymal stem cell treatment for hyperactive immune response in patients with COVID-19.

The human immune system protects the body against invasive organisms and kicks into a hyperactive mode in COVID-19 patients, particularly in those who are critically sick. Therapeutic regimens directed at the hyperactive immune system have been found to be effective in the treatment of patients with COVID-19. An evolving potential treatment option is therapy with mesenchymal stem cells (MSCs) due to their regenerative and reparative ability in epithelial cells. Clinical trials have reported the safe usage of MSC therapy. Systemic effects of MSC treatment have included a reduction in pro-inflammatory cytokines and a decrease in the levels of CRP, IL-6, and lactase dehydrogenase, which function as independent biomarkers for COVID-19 mortality and respiratory failure.

Treatment of COVID-19 is becoming increasingly difficult because of new variants, such as Delta, and more recently Omicron. Each virus variant becomes smarter at being able to evade the body's immune system, vaccines and drug treatments. The biggest challenge in treating COVID-19 is when the body's immune system starts to become hyperactive. In such a scenario, the immune system releases the compounds that are supposed to be released in small doses all at once. Thus, overwhelming the body and causing many complications. One possible solution to this is the mesenchymal stem cell. Multiple clinical trials have shown that mesenchymal stem cells can heal all different cell types in the body and stop the hyperactive immune system.

Association of Gnrhr mRNA With the Stem Cell Determinant Musashi: A Mechanism for Leptin-Mediated Modulation of GnRHR Expression.

The cyclic expression of pituitary gonadotropin-releasing hormone receptors (GnRHRs) may be an important checkpoint for leptin regulatory signals. Gonadotrope Lepr-null mice have reduced GnRHR levels, suggesting these receptors may be leptin targets. To determine if leptin stimulated GnRHR directly, primary pituitary cultures or pieces were exposed to 1 to 100 nM leptin. Leptin increased GnRHR protein levels and the percentages of gonadotropes that bound biotinylated analogs of gonadotropin-releasing hormone (bio-GnRH) but had no effect on Gnrhr messenger RNA (mRNA). An in silico analysis revealed three consensus Musashi (MSI) binding elements (MBEs) for this translational control protein in the 3' untranslated region (UTR) of Gnrhr mRNA. Several experiments determined that these Gnrhr mRNA MBE were active: (1) RNA electrophoretic mobility shift assay analyses showed that MSI1 specifically bound Gnrhr mRNA 3'-UTR; (2) RNA immunoprecipitation of pituitary fractions with MSI1 antibody pulled down a complex enriched in endogenous MSI protein and endogenous Gnrhr mRNA; and (3) fluorescence reporter assays showed that MSI1 repressed translation of the reporter coupled to the Gnrhr 3'-UTR. In vitro, leptin stimulation of pituitary pieces reduced Msi1 mRNA in female pituitaries, and leptin stimulation of pituitary cultures reduced MSI1 proteins selectively in gonadotropes identified by binding to bio-GnRH. These findings show that leptin's direct stimulatory actions on gonadotrope GnRHR correlate with a direct inhibition of expression of the posttranscriptional regulator MSI1. We also show MSI1 interaction with the 3'-UTR of Gnrhr mRNA. These findings now open the door to future studies of leptin-modulated posttranscriptional pathways.