Faculty Bibliography

INTRODUCTION: Devices for male circumcision (MC) are becoming available in 14 priority countries where MC is being implemented for HIV prevention. Understanding potential impact on demand for services is one important programmatic consideration because countries determine whether to scale up devices within MC programs. METHODS: A population-based survey measuring willingness to undergo MC, assuming availability of surgical MC and 3 devices, was conducted among 1250 uncircumcised men, ages 10-49 years in Zambia and 1000 uncircumcised men, ages 13-49 years in Zimbabwe. Simulated Test Market methodology was used to estimate incremental MC demand and the extent to which devices might be preferred over surgery, assuming availability of: surgical MC in both countries; the devices PrePex, ShangRing, and Unicirc in Zambia; and PrePex in Zimbabwe. RESULTS: Modeled estimates indicate PrePex has the potential to provide an overall increase in MC demand ranging from an estimated 13%-50%, depending on country and WHO prequalification ages, replacing 11%-41% of surgical procedures. In Zambia, ShangRing could provide 8% overall increase, replacing 45% of surgical procedures, and Unicirc could provide 30% overall increase, replacing 85% of surgical procedures. CONCLUSIONS: In both countries, devices have potential to increase overall demand for MC, assuming wide scale awareness and availability of circumcision by the devices. With consideration for age and country, PrePex may provide the greatest potential increase in demand, followed by Unicirc (measured in Zambia only) and ShangRing (also Zambia only). These results inform one program dimension for decision making on potential device introduction strategies; however, they must be considered within the broader programmatic context.

In vivo imaging modalities provide powerful tools for the noninvasive longitudinal characterization of preclinical cancer models. Medulloblastoma (MB) is the most common malignant brain tumor in children, and the subject of intense research, much of which involves mouse models. Manganese-enhanced magnetic resonance imaging (MEMRI) produces unparalleled images of the cerebellum, the site of most MBs [1,2]. For this reason, longitudinal MEMRI of preclinical medulloblastoma models enables analysis of the region of origin, monitoring of tumor progression, and treatment response evaluation. In this study, we present the initial MEMRI characterization of a novel mouse medulloblastoma model with an activating mutation in the Smo gene, which exhibit different growth characteristics than those observed in previous studies of Ptch1 knockout mice [1]. SmoM2 mice were engineered by crossing Atoh1-CreER [3] male mice with homozygous R26-floxedSTOP-SmoM2 females [4]. The SmoM2 mutation was induced by subcutaneous injection of low dose (1mug/g) Tamoxifen (TMX) at postnatal day P2. Biweekly imaging sessions using 7-Tesla MRI (Bruker) began at postnatal day P21. MnCl2 (50-60 mg/kg) was injected intraperitoneally 24 hours before imaging. Scan protocol: 1 min low-resolution pilot, 20 min 150mum resolution T1-weighted GE sequence (TE/TR = 4/30 ms; FA = 20degree; FOV = 19.2 mm x 19.2 mm x 12 mm; Matrix = 128 x 128 x 80). Images were analyzed in 3-space using Amira and Fiji. Morphological characterization was corroborated with histology as shown in Fig1. Longitudinal MEMRI results are summarized in Fig2. Based on our preliminary results, all SmoM2 mice had preneoplastic lesions, while approximately half developed into full tumor morphology (n=21). Of the mice with tumors, approximately 72% developed bilateral tumors and the remaining developed tumors in either the right or left hemisphere. Approximately 50% of animals with bilateral tumors exhibited regression in one lateral tumor and progression in the other, or progression in both tumors (n=8). General disease progression is as follows: at approximately postnatal week W3, small lesions are apparent in the majority of interlobule spaces including the mid vermis; at ~W7, regions of proliferative lesion thickening are apparent and smaller lesions regress; at ~W13 significant tumor encroachment into the forebrain as well as expansion of the third and fourth ventricles are apparent. Tumors were observed to originate in the posterior hemispheres, shift and compress the normal appearing cerebellum as they progress, and finally encroach into the forebrain. Estimated tumor volume doubling time is approximately 4.5 days at early timepoints (W11.5). Noticeable symptoms - including delayed tail-pull reflex, ataxia, and hydrocephalus - in SmoM2 mice were apparent as early as W10. In addition to qualitative understanding of tumor progression, we have manually segmented and quantified tumor volume at these key timepoints in an effort to produce a unified growth model. Current efforts in automated segmentation and hierarchical clustering-based classification of tumors will guide upcoming preclinical trials of anticancer therapeutics

Background: Immunological complexity in atherosclerosis warrants targeted treatment of specific inflammatory cells that aggravate the disease. With the initiation of large phase III trials investigating immunomodulatory drugs for atherosclerosis, cardiovascular disease treatment enters a new era. Accordingly, numerous small molecules have been developed to modulate immune cell function, many of which are promising immunotherapy candidates. However, effective immunotherapies require precise effects only on pathological immune cells without causing side effects on the healthy tissues or other immune cells. Results: We here propose a radically different approach that implement and evaluate in vivo a combinatorial library of nanoparticles with distinct physiochemical properties and differential immune cell specificities. The library's nanoparticles are based on endogenous high-density lipoprotein (HDL), which can preferentially deliver therapeutic compounds to pathological immune cells in atherosclerotic plaques^1,2. Using the Apoe ^-/- mouse model of atherosclerosis, we quantitatively evaluated the library's immune cell specificity by combining nanomaterial characterization, in vitro assays, optical imaging, and immunological techniques (a). These distinct physiochemical properties among the library nanoparticles resulted in an approximate 6-fold difference in promoting cholesterol efflux from macrophages, 10-fold difference among blood half-lives, 3.35-fold difference in relative aorta-to-liver accumulation, and 3.84-fold difference in relative aortic-to-splenic macrophage accumulation. In a proof-of-concept study, we identified an ideal drug-delivery nanoparticle with a long blood half-life, low liver retention, and high specificity to atherosclerotic macrophages. We formulated into the nanoparticle (Rx-HDL) a liver receptor X agonist (GW3965), whose high liver toxicity failed its clinical translation. Compared to an undesirable nanoparticle with poor properties for drug delivery (Rx-PLGA-HDL), Rx-HDL minimally retained in the liver while still efficiently delivered GW3965 to atherosclerotic plaques, revealed by in vivo PET imaging and ex vivo flow cytometry. In a one-week intensive treatment regimen in atherosclerotic mice, Rx-HDL totally abolished GW3965's liver toxicity (b ). Finally, a 6-week long-term treatment with Rx-HDL produced significant therapeutic effects on atherosclerotic plaques (c). Conclusion: In this study, for the first time, we demonstrate a systemic in vivo immune cell screening of a nanoparticle library can produce effective immunotherapy for atherosclerosis. Screening the immune cell specificity of nanoparticles can be employed to develop tailored therapies for atherosclerosis and other inflammatory diseases. [IMAGE PRESENTED]

Depending on the tissue microenvironment, T cells can differentiate into highly diverse subsets expressing unique trafficking receptors and cytokines. Studies of human lymphocytes have primarily focused on a limited number of parameters in blood, representing an incomplete view of the human immune system. Here, we have utilized mass cytometry to simultaneously analyze T cell trafficking and functional markers across eight different human tissues, including blood, lymphoid, and non-lymphoid tissues. These data have revealed that combinatorial expression of trafficking receptors and cytokines better defines tissue specificity. Notably, we identified numerous T helper cell subsets with overlapping cytokine expression, but only specific cytokine combinations are secreted regardless of tissue type. This indicates that T cell lineages defined in mouse models cannot be clearly distinguished in humans. Overall, our data uncover a plethora of tissue immune signatures and provide a systemic map of how T cell phenotypes are altered throughout the human body.

Background/Purpose: We aimed to understand the mechanism by which membrane-type 1 matrix metalloproteinase (MT1-MMP, MMP-14) controls bone and cartilage homeostasis. MT1-MMP, a cell-membrane-bound proteinase with an extracellular catalytic site and a 20-amino acid cytoplasmic tail, plays a key role in postnatal bone formation. The genetic deficiency of MT1-MMP in the mouse causes dwarfism, osteopenia and severe arthritis. Deletion of MT1-MMP in bone marrow-derived mesenchymal progenitor cells (BM-MSC) recapitulates this phenotype, showing that MT1-MMP controls osteogenic differentiation in MSC. The phenotype of MT1-MMP-/- mice has been proposed to result from lack of MT1-MMP proteolytic activity. However, mounting evidence shows a variety of proteolysis-independent signaling functions of MT1-MMP. The unique tyrosine (Y573) in the MT1-MMP cytoplasmic tail is fundamental for the control of intracellular signaling. Methods: We generated a mouse with the Y573D mutation in MT1-MMP (MT1-MMP Y573D) and characterized its skeletal phenotype by histological and microCT analyses. Isolated BM-MSC were induced to differentiate into osteoblasts, chondrocytes and adipocytes, using qRT-PCR to analyze gene expression. Mouse C3H10T1/2 MSC were transfected with MT1-MMP cDNA and analyzed for Wnt signaling by luciferase reporter assays. Results: MT1-MMP Y573D mice had increased trabecular bone relative to wt littermates, marked thinning of articular cartilage with disorganized tissue architecture, clustering and cloning of chondrocytes, and pronounced decrease in bone marrow-associated and total body fat. We induced BM-MSC from wt and MT1-MMP Y573D littermates to differentiate into osteoblast and chondrocytes, and myeloid precursors into osteoclasts. The Y573D mutation dramatically increased MSC expression of osteoblast markers and strongly downregulated chondrocyte and osteoclast markers. These findings indicated that Wnt signaling is upregulated in MT1-MMP Y573D-expressing MSC. Therefore, we analyzed Wnt signaling. We transiently transfected C3H10T1/2 MSC cells in osteoblast medium with the cDNAs for wt MT1-MMP and MT1-MMP Y573D. As controls the cells were transfected with the empty vector (pcDNA) or with MT1-MMP E240A, a mutant devoid of proteolytic activity. MT1-MMP Y573D dramatically upregulated Wnt signaling relative to wt MT1-MMP and MT1-MMP E240A. Conclusion: MT1-MMP controls Wnt signaling by a mechanism independent of extracellular proteolysis and mediated by its cytoplasmic tail. MT1-MMP is a bifunctional protein, with an extracellular proteolytic activity that promotes bone formation through ECM remodeling and a cytoplasmic tail that controls osteogenesis by interacting with a key pro-osteogenic signaling pathway