Effects of the iron oxide nanoparticle Molday ION Rhodamine B on the viability and regenerative function of neural stem cells: relevance to clinical translation

Abstract

An essential component of developing successful neural stem cell (NSC)-based therapies involves the establishment of methodologies to noninvasively monitor grafted NSCs within brain tissues in real time. In this context, ex vivo labeling with ultrasmall superparamagnetic iron oxide (USPIO) particles has been shown to enable efficient tracking of transplanted NSCs via magnetic resonance imaging (MRI). However, whether and how USPIO labeling affects the intrinsic biology of NSCs is not thoroughly understood, and remains an active area of investigation. Here, we perform a comprehensive examination of rat NSC survival and regenerative function upon labeling with the USPIO, Molday ION Rhodamine B (MIRB), which allows for dual magnetic resonance and optical imaging. After optimization of labeling efficiency, two specific doses of MIRB (20 and 50 μg/mL) were chosen and were followed for the rest of the study. We observed that both MIRB doses supported the robust detection of NSCs, over an extended period of time in vitro and in vivo after transplantation into the striata of host rats, using MRI and post hoc fluorescence imaging. Both in culture and after neural transplantation, the higher 50 μg/mL MIRB dose significantly reduced the survival, proliferation, and differentiation rate of the NSCs. Interestingly, although the lower 20 μg/mL MIRB labeling did not produce overtly negative effects, it increased the proliferation and glial differentiation of the NSCs. Additionally, application of this dose also changed the morphological characteristics of neurons and glia produced after NSC differentiation. Importantly, the transplantation of NSCs labeled with either of the two MIRB doses upregulated the immune response in recipient animals. In particular, in animals receiving the 50 μg/mL MIRB-labeled NSCs, this immune response consisted of an increased number of CD68 + -activated microglia, which appeared to have phagocytosed MIRB particles and cells contributing to an exaggerated MRI signal dropout in the animals. Overall, these results indicate that although USPIO particles, such as MIRB, may have advantageous labeling and magnetic resonance-sensitive features for NSC tracking, a further examination of their effects might be necessary before they can be used in clinical scenarios of cell-based transplantation.

Redox-active nanomaterials for nanomedicine applications

“…In practice, these morphology alterations could have massive ramifications for in vitro production and in vivo grafting of SPION-labeled NSCs. 50 In vivo measurements of contrast signal, NSC graft size (a measure of NSC viability), and proliferation all generally agreed with the in vitro results: the 50-μg dosed group had more adverse outcomes than the 20-μg dosed group. In all circumstances, increased ROS production resulting from the presence of SPION was suggested to be the major contributor to the observed differences between the control and MIRB-treated NSCs.…”

“…Umashankar et al 50 also studied the effects of SPIONs on NSCs; specifically, the influence of Molday ION Rhodamine B (MIRB) (a commercially available SPION used for cell labelling, tracking, and MRI) on the survival and regenerative capacity of rat NSCs both in vitro and in vivo . While the NSCs could be detected when labeled at both doses (20 μg and 50 μg) of MIRB, the higher dose was found to increase MRI contrast signal, which seems to be an unsurprising result.…”

Development and validation of broad-spectrum magnetic particle labelling processes for cell therapy manufacturing

“…MP-labelled neuroprogenitors were demonstrated to retain the ability to readily differentiate following simulated cold chain transport, as seen for unlabelled cells. This is in line with previous findings which demonstrated a retention of differentiation capacity following labelling [ 77 ]. Additionally, whilst both studies demonstrate retention of differentiation capacity, there are likely underlying long-term biological consequences.…”

“…Additionally, whilst both studies demonstrate retention of differentiation capacity, there are likely underlying long-term biological consequences. This is reflected in the observations during this research and previous literature [ 77 ] showing changes to cell morphology. This is potentially driven by the production of reactive oxygen species by the iron particles within the cells which are able to alter the internal regulatory mechanisms of neural stem cells [ 78 ].…”

Imaging Gliomas with Nanoparticle-Labeled Stem Cells

“…[ 30 ] Other studies on this topic have further developed the research on NSC-based drug administration,[ 31 32 ] gene therapy,[ 33 34 ] and application of the bystander effect. [ 35 36 37 ] Conversely, the incorporation of nanomedicine to NSCs has led to extensive research in this realm, including the effect of nanomaterials on NSC biology,[ 38 39 40 41 ] enhanced material loading,[ 42 43 44 45 ] stem cell tracking,[ 46 47 48 49 50 51 ] and tumor treatment. [ 32 52 ]…”