Assessment of the Immunosuppressive Potential of INF-γ Licensed Adipose Mesenchymal Stem Cells, Their Secretome and Extracellular Vesicles.

There is an active search for the ideal strategy to potentialize the effects of Mesenchymal Stem-Cells (MSCs) over the immune system. Also, part of the scientific community is seeking to elucidate the therapeutic potential of MSCs secretome and its extracellular vesicles (EVs), in order to avoid the complexity of a cellular therapy. Here, we investigate the effects of human adipose MSCs (AMSCs) licensing with INF-γ and TLR3 agonist over AMSCs proliferation, migration, as well as the immunomodulatory function. Furthermore, we evaluated how the licensing of AMSCs affected the immunomodulatory function of AMSC derived-secretome, including their EVs. INF-γ licensed-AMSCs presented an elevated expression of indoleamine 2,3-dioxygenase (IDO), accompanied by increased ICAM-1, as well as a higher immunosuppressive potential, compared to unlicensed AMSCs. Interestingly, the conditioned medium obtained from INF-γ licensed-AMSCs also revealed a slightly superior immunosuppressive potential, compared to other licensing strategies. Therefore, unlicensed and INF-γ licensed-AMSCs groups were used to isolate EVs. Interestingly, EVs isolated from both groups displayed similar capacity to inhibit T-cell proliferation. EVs isolated from both groups shared similar TGF-ß and Galectin-1 mRNA content but only EVs derived from INF-γ licensed-AMSCs expressed IDO mRNA. In summary, we demonstrated that INF-γ licensing of AMSCs provides an immunosuppressive advantage both from a cell-cell contact-dependent perspective, as well as in a cell-free context. Interestingly, EVs derived from unlicensed and INF-γ licensed-AMSCs have similar ability to control activated T-cell proliferation. These results contribute towards the development of new strategies to control the immune response based on AMSCs or their derived products.

Unraveling KDM4 histone demethylase expression and its association with adverse cytogenetic findings in chronic lymphocytic leukemia.

The acquisition of complex karyotypes is related to the progression of chronic lymphocytic leukemia (CLL) and patients with this condition have a poor prognosis. Despite recent advances in the classification of prognosis in CLL patients, understanding of the molecular mechanisms that lead to genomic instability and progression of this disease remains inadequate. Interestingly, dysregulated expression of KDM4 members is involved in the progression of several cancer types and plays a role in the DNA damage response; however, the gene expression profile and the importance of KDM4 members in CLL are still unknown. Here, we assessed the gene expression profile of KDM4A, KDM4B, and KDM4C in 59 CLL samples and investigated whether these histone demethylases have any influence on the prognostic markers of this leukemia. KDM4A gene expression was higher in CLL patients as compared with control samples. In contrast, CLL samples showed decreased levels of the KDM4B transcript in relation to control cases, and no difference was detected in KDM4C expression. Furthermore, patients with positive expression of ZAP-70 had lower expression of KDM4B and KDM4C as compared with ZAP-70-negative patients. More importantly, patients with low expression of these histone demethylases had higher leukemic cell numbers and displayed adverse cytogenetic findings and the acquisition of a complex karyotype. The present data clearly show that the expression of KDM4 members is dysregulated in CLL and impact the prognosis of this leukemia. These findings are useful for a better understanding of the impact of epigenetics on CLL progression.

LL-37 treatment on human peripheral blood mononuclear cells modulates immune response and promotes regulatory T-cells generation.

LL-37 is a host-defense peptide (HDP) and exerts a broad spectrum of microbicidal activity against bacteria, fungi, and viral pathogens. This peptide also interacts with human cells and influences their behavior, promoting angiogenesis, wound healing, immunomodulation, and affecting apoptosis. Lately, significant advances have been achieved regarding the elucidation of underlying mechanisms related to LL-37 effects over neutrophil and monocytes. However, how T-cells respond to LL-37 stimulation is still largely unknown. Here, we used flow cytometry to evaluate the effects of LL-37 over peripheral blood mononuclear cells (PBMCs) viability, T-cell proliferation, T-cell activation, as well as the generation of regulatory T-cells (Tregs). Those aspects were assessed both in immune homeostatic and inflammatory milieu. Furthermore, we investigated the transcript levels of the inflammatory factors INF-γ, TNF-ɑ, and TGF-ß in these conditions. Interestingly, our data revealed that the treatment of PBMCs with LL-37 enhanced the viability of these cells and exerted wide effects over T cell response. Upon activation, LL-37 treated T-cells presented lower proliferation and also increased generation of Tregs. Finally, while non-stimulated cells increased the expression of inflammatory factors when treated with LL-37, activated cells treated with LL-37 presented a decreased production of the same inflammatory mediators. These results are important for the immunotherapy field, and indicate that the use of LL-37 must be carefully evaluated in both homeostatic and inflammatory scenarios, since the microenvironment clearly plays a crucial role in determining how T-cells respond to LL-37.

GLP overexpression is associated with poor prognosis in Chronic Lymphocytic Leukemia and its inhibition induces leukemic cell death.

Background Heterodimeric methyltransferases GLP (EHMT1/KMT1D) and G9a (EHMT2/KMT1C) are two closely related enzymes that promote the monomethylation and dimethylation of histone H3 lysine 9. Dysregulation of their activity has been implicated in several types of human cancer. Patients and methods Here, in order to investigate whether GLP/G9a exerts any impact on Chronic Lymphocytic Leukemia (CLL), GLP/G9a expression levels were assessed in a cohort of 50 patients and the effects of their inhibition were verified for the viability of CLL cells. Also, qRT-PCR was used to investigate the transcriptional levels of GLP/G9a in CLL patients. In addition, patient samples were classified according to ZAP-70 protein expression by flow cytometry and according to karyotype integrity by cytogenetics analysis. Finally, a selective small molecule inhibitor for GLP/G9a was used to ascertain whether these methyltransferases influenced the viability of MEC-1 CLL cell lineage. Results mRNA analysis revealed that CLL samples had higher levels of GLP, but not G9a, when compared to non-leukemic controls. Interestingly, patients with unfavorable cytogenetics showed higher expression levels of GLP compared to patients with favorable karyotypes. More importantly, GLP/G9a inhibition markedly induced cell death in CLL cells. Conclusion Taken together, these results indicate that GLP is associated with a worse prognosis in CLL, and that the inhibition of GLP/G9a influences CLL cell viability. Altogether, the present data demonstrate that these methyltransferases can be potential markers for disease progression, as well as a promising epigenetic target for CLL treatment and the prevention of disease evolution.