Immune potency of bioreactor-aged dendritic cells in 3D collagen matrices

Abstract

The processes of aging and space travel both have significant adverse effects on the immune system, resulting in increased susceptibility to infections. Using simulated microgravity platforms, such as the random positioning machine (RPM), on Earth allows us to investigate these effects to better facilitate future space travel and our understanding of the aging immune system. Dendritic cells (DCs) are key players in linking the innate and adaptive immune responses. Their distinct differentiation and maturation phases play vital roles in presenting antigens and mounting effective T-cell responses. However, DCs primarily reside in tissues such as the skin and lymph nodes. To date, no studies have effectively investigated the effects of aging via RPM on DCs in their native microenvironment. With 3D biomimetic collagen hydrogels, we can study the effects on DCs in more physiologically relevant microenvironments. In this study, we investigated the effects of loose and dense culture matrices on the phenotype, function, and transcriptome profile of immature and mature DCs utilizing an RPM to simulate an accelerated aging model. Our data indicate that an aged, or loose tissue microenvironment, and exposure to RPM conditions decrease the immunogenicity of iDCs and mDCs. Interestingly, cells cultured in dense matrices experienced fewer effects by the RPM at the transcriptome level.

Tissue-bound hyaluronan molecular weight as a regulator of dendritic cell immune potency

“…For this purpose, human monocytic THP-1 cells were differentiated into mDCs using GM-CSF, IL-4, TNFα, and ionomycin for a period of 3 days. Previously, we have demonstrated the effectiveness of this differentiation protocol in generating mDCs with increased levels of costimulatory molecules, MHC proteins, and upregulated immune response pathway genes compared to iDCs, as evidenced by surface marker analysis, cytokine secretion, and transcriptomic profiling [49].…”

“…Surprisingly, our results revealed no significant differences in the surface marker expressions of CCR7, HLA-DR, and CD86 on mDCs across all matrix conditions, regardless of the presence of CD44 (Figure 5E). It has been hypothesized that as DCs mature, they become less responsive to external stimuli [49]. In addition to the analysis of mDC-specific cell surface markers, we examined the cytokine secretion profiles of mDCs in different matrix conditions (Figure 5F).…”