4 research outputs found
CD4+Foxp3+T Regulatory Cells Promote Transplantation Tolerance by Modulating Effector CD4+ T Cells in a Neuropilin-1-Dependent Manner
Several mechanisms of immune suppression have been attributed to Foxp3+ T regulatory cells (Treg) including modulation of target cells via inhibition of cell proliferation, alteration of cytokine secretion, and modification of cell phenotype, among others. Neuropilin-1 (Nrp1), a co-receptor protein highly expressed on Treg cells has been involved in tolerance-mediated responses, driving tumor growth and transplant acceptance. Here, we extend our previous findings showing that, despite expressing Foxp3, Nrp1KO Treg cells have deficient suppressive function in vitro in a contact-independent manner. In vivo, the presence of Nrp1 on Treg cells is required for driving long-term transplant tolerance. Interestingly, Nrp1 expression on Treg cells was also necessary for conventional CD4+ T cells (convT) to become Nrp1+Eos+ T cells in vivo. Furthermore, adoptive transfer experiments showed that the disruption of Nrp1 expression on Treg cells not only reduced IL-10 production on Treg cells, but also increased the frequency of IFNγ+ Treg cells. Similarly, the presence of Nrp1KO Treg cells facilitated the occurrence of IFNγ+CD4+ T cells. Interestingly, we proved that Nrp1KO Treg cells are also defective in IL-10 production, which correlates with deficient Nrp1 upregulation by convT cells. Altogether, these findings demonstrate the direct role of Nrp1 on Treg cells during the induction of transplantation tolerance, impacting indirectly the phenotype and function of conventional CD4+ T cells
Tr1 cells reside within the tumor microenvironment: Comparison with conventional Foxp3+ T regulatory cells.
Seminario de Título para optar al Título de Ingeniera en Biotecnología Molecular.La función supresora de las células T reguladoras (Tregs) puede tener efectos negativos
sobre la respuesta inmune antitumoral. Por lo tanto, es de gran importancia estudiar los
factores que alteran la eficiencia de su inhibición, de tal forma de poder mejorar las
terapias antitumorales. La alta heterogeneidad de las Tregs periféricas es uno de los
problemas que deben ser abordados para mejorar y desarrollar nuevas terapias
antitumorales. Dentro del subset de Tregs, nuevos marcadores superficiales para la
población T reguladora tipo 1 (Tr1) no-clásica han sido reportados recientemente,
permitiendo su identificación mediante la expresión de las moléculas CD49b y LAG-3 en
su superficie. El efecto terapéutico de la población identificada mediante estos marcadores
ya ha sido estudiado en modelos murinos de diabetes y de artritis inducida por colágeno,
en los cuales mostraron un efecto protector. Sin embargo, su rol en el contexto tumoral ha
sido poco estudiado. Es por esto por lo que buscamos caracterizar a la población Tr1,
identificada mediante la expresión de CD49b, en un modelo murino de melanoma.
Sorprendentemente, se encontró que su presencia parece estar fuertemente influenciada
por el microambiente en el cual se encuentra. Mientras que en los linfonodos drenantes de tumor (TdLNs) este subset compone tan solo el 4% del total de células T CD4+, en el
tumor alcanzan un 30% de las células T CD4+. Por otra parte, las Tregs convencionales
Foxp3+ (cTregs), componen alrededor de un 15% de los linfocitos que infiltran el tumor
(TILs) que expresan CD4, casi la mitad de lo observado para las Tr1. En cuanto a su
fenotipo, se observó que, aunque en menores niveles que las cTregs, alrededor del 50% y
30% de las Tr1 expresan Nrp1, en los TdLNs y en el tumor, respectivamente. Esta
molécula es un co-receptor de VEGF, y se ha descrito que es esencial para la estabilidad
y función del fenotipo supresor de las cTreg y para la progresión tumoral. Además, se
observó que las Tr1 muestran un patrón diferencial de expresión de ciertas moléculas
reguladoras, comparado con las cTregs: una mayor intensidad mediana de fluorescencia
de la ectonucleotidasa CD73 en el tumor, contrario a lo que se observa en los TdLNs, y
una menor producción de IL-10 en el tumor. Se encontró además que la capacidad
proliferativa de las cTregs es significativamente mayor a la de las Tr1, tanto en el tumor
como en los TdLNs. Así, nuestros resultados destacan las posibles diferencias entre los
mecanismos de inmunosupresión de los subsets de Tregs, los cuales pueden variar
dependiendo del microambiente (TdLNs versus tumor).T regulatory cells (Tregs) suppressive function can have a detrimental effect on immune
responses against tumor cells. Thus, in order to improve actual anti-tumor therapies, it is
of great importance to study the factors altering their inhibition efficiency. The high
heterogeneity of peripheral Tregs is one of the problems that have to be addressed to
enhance and develop novel anti-tumoral therapies. Within the Tregs subsets, new surface
markers for the non-classical type 1 regulatory T cells population (Tr1) have been recently
reported, allowing their identification through the expression of the CD49b and LAG-3
molecules. Their therapeutic effect has already been studied in murine models of diabetes
and collagen-induced-arthritis, in which they displayed a protective effect. Nevertheless,
very few studies have focused on investigating their role in the tumoral context. Thus, we
sought to investigate the function of the Tr1 cell subset, identified through the expression
of CD49b, in a murine melanoma model. Surprisingly, we found that their presence seems
to be strongly influenced by the microenvironment they encounter. Whereas in the tumor
draining lymph nodes (TdLNs) this subset composes only around 4% of total CD4+ T
cells, in the tumor, they compose almost 30% of CD4+ T cells. On the other hand,
conventional Fopx3+ Tregs (cTregs) compose around 15% of CD4+ tumor-infiltrating T
cells, almost half of the percentage of Tr1 cells. Regarding their phenotype, we observed
that, although in lower levels than cTregs, around 50 and 30% of Tr1 cells express
Neuropilin-1 (Nrp1), in the TdLNs and in the tumor, respectively. Nrp1 is a VEGF co
receptor, which has been described to be essential for the stability and function of cTregs
suppressive phenotype and in tumor progression. Even more, we also observed that Tr1
cells show a differential pattern of expression of some regulatory molecules, compared to
cTregs: a higher median fluorescence of the ectonucleotidase CD73 in the tumor
microenvironment, contrary to what is seen in the TdLNs, and a lower production of IL
10 in the tumor. Furthermore, we found that the proliferative capacity of cTregs is
significantly higher to Tr1 cells, both in the tumor and in the TdLNs. Thus, our results
further highlight the possible differences between the immunosuppression mechanisms of
the Tregs subsets depending on the microenvironment (TdLNs versus tumor site)
Type I collagen hydrogels as a delivery matrix for royal jelly derived extracellular vesicles
Throughout the last decade, extracellular vesicles (EVs) have become increasingly popular in several areas of regenerative medicine. Recently, Apis mellifera royal jelly EVs (RJ EVs) were shown to display favorable wound healing properties such as stimulation of mesenchymal stem cell migration and inhibition of staphylococcal biofilms. However, the sustained and effective local delivery of EVs in non-systemic approaches – such as patches for chronic cutaneous wounds – remains an important challenge for the development of novel EV-based wound healing therapies. Therefore, the present study aimed to assess the suitability of type I collagen -a well-established biomaterial for wound healing – as a continuous delivery matrix. RJ EVs were integrated into collagen gels at different concentrations, where gels containing 2 mg/ml collagen were found to display the most stable release kinetics. Functionality of released RJ EVs was confirmed by assessing fibroblast EV uptake and migration in a wound healing assay. We could demonstrate reliable EV uptake into fibroblasts with a sustained pro-migratory effect for up to 7 d. Integrating fibroblasts into the RJ EV-containing collagen gel increased the contractile capacity of these cells, confirming availability of RJ EVs to fibroblasts within the collagen gel. Furthermore, EVs released from collagen gels were found to inhibit Staphylococcus aureus ATCC 29213 biofilm formation. Overall, our results suggest that type I collagen could be utilized as a reliable, reproducible release system to deliver functional RJ EVs for wound healing therapies
T regulatory cells-derived extracellular vesicles and their contribution to the generation of immune tolerance
T regulatory (Treg) cells have a major role in the maintenance of immune tolerance against self and foreign antigens through the control of harmful inflammation. Treg cells exert immunosuppressive function by several mechanisms, which can be distinguished as contact dependent or independent. Recently, the secretion of extracellular vesicles (EVs) by Treg cells has been reported as a novel suppressive mechanism capable of modulating immunity in a cell-contact independent and targeted manner, which has been identified in different pathologic scenarios. EVs are cell-derived membranous structures involved in physiologic and pathologic processes through protein, lipid, and genetic material exchange, which allow intercellular communication. In this review, we revise and discuss current knowledge on Treg cells-mediated immune tolerance giving special attention to the production and release of EVs. Multiple studies support that Treg cells-derived EVs represent a refined intercellular exchange device with the capacity of modulating immune responses, thus creating a tolerogenic microenvironment in a cell-free manner. The mechanisms proposed encompass miRNAs-induced gene silencing, the action of surface proteins and the transmission of enzymes. These observations gain relevance by the fact that Treg cells are susceptible to converting into effector T cells after exposition to inflammatory environments. Yet, in contrast to their cells of origin, EVs are unlikely to be modified under inflammatory conditions, highlighting the advantage of their use. Moreover, we speculate in the possibility that Treg cells may contribute to infectious tolerance via vesicle secretion, intervening with CD4(+)T cells differentiation and/or stability.National Scholarship CONICYT
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