Low Dose Focused Ultrasound Induces Enhanced Tumor Accumulation of Natural Killer Cells

Natural killer (NK) cells play a vital antitumor role as part of the innate immune system. Efficacy of adoptive transfer of NK cells depends on their ability to recognize and target tumors. We investigated whether low dose focused ultrasound with microbubbles (ldbFUS) could facilitate the targeting and accumulation of NK cells in a mouse xenograft of human colorectal adenocarcinoma (carcinoembryonic antigen (CEA)-expressing LS-174T implanted in NOD.Cg-Prkdc^(scid)Il2rg^(tm1Wjl)/SzJ (NSG) mice) in the presence of an anti-CEA immunocytokine (ICK), hT84.66/M5A-IL-2 (M5A-IL-2). Human NK cells were labeled with an FDA-approved ultra-small superparamagnetic iron oxide particle, ferumoxytol. Simultaneous with the intravenous injection of microbubbles, focused ultrasound was applied to the tumor. In vivo longitudinal magnetic resonance imaging (MRI) identified enhanced accumulation of NK cells in the ensonified tumor, which was validated by endpoint histology. Significant accumulation of NK cells was observed up to 24 hrs at the tumor site when ensonified with 0.50 MPa peak acoustic pressure ldbFUS, whereas tumors treated with at 0.25 MPa showed no detectable NK cell accumulation. These clinically translatable results show that ldbFUS of the tumor mass can potentiate tumor homing of NK cells that can be evaluated non-invasively using MRI

In Vivo Monitoring of Natural Killer Cell Trafficking During Tumor Immunotherapy

Natural killer (NK) cells are a crucial part of the innate immune system and play critical roles in host anti-viral, anti-microbial, and antitumor responses. The elucidation of NK cell biology and their therapeutic use are actively being pursued with 200 clinical trials currently underway. In this review, we outline the role of NK cells in cancer immunotherapies and summarize current noninvasive imaging technologies used to track NK cells in vivo to investigate mechanisms of action, develop new therapies, and evaluate efficacy of adoptive transfer

Bridging the gap: Mechanisms of plasticity and repair after pediatric TBI.

Traumatic brain injury is the leading cause of death and disability in the United States, and may be associated with long lasting impairments into adulthood. The multitude of ongoing neurobiological processes that occur during brain maturation confer both considerable vulnerability to TBI but may also provide adaptability and potential for recovery. This review will examine and synthesize our current understanding of developmental neurobiology in the context of pediatric TBI. Delineating this biology will facilitate more targeted initial care, mechanism-based therapeutic interventions and better long-term prognostication and follow-up

D-Cycloserine Restores Experience-Dependent Neuroplasticity after Traumatic Brain Injury in the Developing Rat Brain

Traumatic brain injury (TBI) in children can cause persisting cognitive and behavioral dysfunction, and inevitably raises concerns about lost potential in these injured youth. Lateral fluid percussion injury (FPI) in weanling rats pathologically affects hippocampal N-methyl-d-aspartate receptor (NMDAR)- and α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid receptor (AMPAR)-mediated glutamatergic neurotransmission subacutely within the first post-injury week. FPI to weanling rats has also been shown to impair enriched-environment (EE) induced enhancement of Morris water maze (MWM) learning and memory in adulthood. Recently, improved outcomes can be achieved using agents that enhance NMDAR function. We hypothesized that administering D-cycloserine (DCS), an NMDAR co-agonist, every 12 h (i.p.) would restore subacute glutamatergic neurotransmission and reinstate experience-dependent plasticity. Postnatal day 19 (P19) rats received either a sham or FPI. On post-injury day (PID) 1-3, animals were randomized to saline (Sal) or DCS. Firstly, immunoblotting of hippocampal NMDAR and AMPAR proteins were measured on PID4. Second, PID4 novel object recognition, an NMDAR- and hippocampal- mediated working memory task, was assessed. Third, P19 rats were placed in an EE (17 days), and MWM performance was measured, starting on PID30. On PID4, DCS restored reduced NR2A and increased GluR2 by 54%, and also restored diminished recognition memory in FPI pups. EE significantly improved MWM performance in shams, regardless of treatment. In contrast, FPI-EE-Sal animals only performed to the level of standard housed animals, whereas FPI-EE-DCS animals were comparable with sham-EE counterparts. This study shows that NMDAR agonist use during reduced glutamatergic transmission after developmental TBI can reinstate early molecular and behavioral responses that subsequently manifest in experience-dependent plasticity and rescued potential

Relaxation rate is linear in Fe labeled NK cell concentration.

<p>Ferumoxytol labeled NK cells were suspended in both 26% Ficoll and 1% agar solutions and R₂* determined at 7T using 2D MGE protocol (mean±SD). There is no significant difference between fitted slopes and intercepts of Fe-NK suspensions in 26% Ficoll and 1% agar solutions.</p

NK cell concentration in tumors determined from ΔR₂*.

<p>Although NK cell tumor distributions are heterogeneous as seen in <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0142767#pone.0142767.g003" target="_blank">Fig 3</a>, R₂* geometric means were obtained by fitting the R₂* histogram to a lognormal distribution. NK cell concentrations (10⁶/ml, mean±SD) in tumor tissue obtained from ΔR₂* determination and the linear relationship between R₂* and NK cell concentration shown in <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0142767#pone.0142767.g002" target="_blank">Fig 2</a>. Planned comparisons were performed using the Student’s t-test. Significant differences are indicated by *p<0.05 and **p<0.01.</p

Diagram of <i>ldb</i>FUS setup.

<p><i>ldb</i>FUS transducer and hydrophone (Sonic Concepts H107 & Y107) are fixed in a plastic coupling cone filled with degassed water and sealed with a thin membrane. Ultrasound gel between membrane & tumor ensure good sonic contact. Focal region of <i>ldb</i>FUS transducer is ~5mm diameter & 15mm long; centered below the coupling membrane and within the tumor.</p

Quantitation of % NK cells from fluorescent staining of tumors from an NSG mouse.

<p>(A) Fluorescent NK cells (CD56, red) and DAPI (blue) staining of tumors from an NSG mouse: upper panel from tumor administered <i>ldb</i>FUS/0.50 MPa; lower panel from contralateral tumor that was not treated. Scale bar = 50 μm. (B) A sample section with positive-NK-CSFE (green) in tumor tissue (DAPI, blue). Scale bar = 50 μm. (C) Mean±SD Percent % NK cells determined from CD56 and CSFE fluorescent staining. % NK cells = number of NK cells / total number of cells (determined from DAPI stain). Planned comparisons using t-test showed a significant difference between (-)<i>ldb</i>FUS and (+)<i>ldb</i>FUS, **p<0.01.</p