Detection and Identification of Old World Leishmania by High Resolution Melt Analysis

Protozoal parasites of the genus Leishmania are transmitted by sand fly bites to humans and animals. Three major forms of disease are caused by these parasites: cutaneous leishmaniasis, responsible for disfiguring skin wounds; mucocutaneous leishmaniasis, causing non-healing ulceration around the mouth and nose; and the potentially fatal visceral leishmaniasis, involving internal organs such as the spleen and liver. More than 2 million new human infections are caused annually by leishmaniasis globally, it is endemic in more than 88 countries and prevalent also as an imported disease in non-endemic regions due to travel and tourism. Most species of Leishmania that infect humans are zoonotic and transmitted from animal reservoir hosts. As various leishmanial parasites cause disease with similar symptoms, but require different therapeutic regimens and have dissimilar prognoses, reliable, sensitive and rapid diagnostic assays are needed. This study focuses on the five main species that cause leishmaniasis in the Old World. It presents a new assay for rapid detection, species identification and quantification of leishmanial parasites in clinical samples, reservoir hosts and sand flies. This technique could be especially valuable in regions where several leishmanial species exist, in non-endemic regions where infected patients require a rapid diagnosis, and for epidemiological host and vector studies leading to prevention programs

Leishmania tropica Infection in Golden Jackals and Red Foxes, Israel

During a survey of wild canids, internal transcribed spacer 1 real-time PCR and high-resolution melt analysis identified Leishmania tropica in samples from jackals and foxes. Infection was most prevalent in ear and spleen samples. Jackals and foxes may play a role in the spread of zoonotic L. tropica

Leishmania tropica in Rock Hyraxes (Procavia capensis) in a Focus of Human Cutaneous Leishmaniasis

Cutaneous leishmaniasis, caused by Leishmania tropica, has recently emerged in urban and rural foci of central and northern Israel, and constitutes a major public health concern. Rock hyraxes (Procavia capensis), the suspected natural reservoir, were trapped in the cutaneous leishmaniasis urban focus of Maale Adumim in central Israel and evaluated for L. tropica infection by real-time kinetoplast DNA (kDNA) polymerase chain reaction (PCR) and serology. Real-time PCR on blood and computerized western blot serology analysis was positive for L. tropica in 58% and 80%, respectively, of the hyraxes tested. Phylogenetic analysis of the ribosomal internal transcribed spacer 1 region indicated that similar genotypes were present in humans and hyraxes from the same habitat. The high rates of infection and exposure to L. tropica among hyraxes supports their involvement in the transmission cycle of this parasite, and their potential role as a reservoir for human disease

Abstract 4724: Targeting matrix metalloproteinases (MMP) for anti-metastatic therapy: Blocking active MMP9 abrogates metastatic niche formation and prevents metastatic seeding in a breast cancer model

Abstract Currently there is no cure for a metastatic disease and it is therefore critical to target the early events that foster metastasis. It is now also recognized that a favorable microenvironment in the metastatic site, primed by the tumor, is crucial for metastasis. Our study is geared towards deciphering cellular and molecular mechanisms governing the metastatic niche that may lead to novel targeted anti-metastatic therapeutics. We utilize the multi-stage MMTV-PyMT breast cancer mouse model, which shares significant similarities with human breast cancer. By injecting a reporter metastatic cell line into hyperplasia-bearing mice, we were able to probe the susceptibility of the lung microenvironment to metastatic seeding. We demonstrate that early during mammary tumorigenesis, before metastasis has occurred, a metastatic niche is formed in the lung microenvironment. This niche is initiated in part by tumor-induced systemic pro-inflammatory factors and local extracellular matrix remodelers, as matrix metalloproteinases (MMPs). We show that the metastatic niche is associated with MMP9-expressing CD11b+Gr1+ and other lung stromal cells. MMP9, which is also expressed by tumor cells, appears as a pivotal player in the process and is therefore considered as a desirable therapeutic target. To examine the role of MMP9 activity in lung metastatic colonization, we utilized novel endogenous-like, function-specific antibodies (SDS3) that block the transiently-activated enzyme conformation of MMP9, which presumably contributes to disease progression. The therapeutic potential of SDS3 has been demonstrated in models of inflammatory bowel disease. We show that metastatic seeding within the lung microenvironment can be inhibited by SDS3, not only in experimental metastasis models but also when the lung microenvironment is primed by hyperplastic mammary tumors. Primary tumor burden was not changed with SDS3, suggesting that blocking active MMP9 is effective in preventing early metastasis rather than established tumors. To study the biodistribution and pharmacokinetics of SDS3, we utilized whole-body bioluminescence, intravital and ex-vivo live microscopy as well as flow cytometry. We show that SDS3 is retained in myeloid cells within the microenvironment of mammary tumors and lung metastatic foci. In situ zymography shows high MMP activity in premetastaic MMTV-PyMT lungs, which is reduced after SDS3. SDS3 also inhibits colony formation of cultured metastatic cells. Our results suggest that a metastatic niche is present in the lungs of hyperplastic mammary tumor-bearing mice and that it can be targeted by blocking MMP9 activity. Our study offers new insights into effectively blocking the in vivo activity of dysregulated MMPs as early anti-metastatic therapy of various cancers. Citation Format: Vicki Plaks, Jonathan Chou, Carrie Maynard, Nguyen H. Nguyen, Niwen Kong, Inna Solomonov, Dalit Talmi-Frank, Caroline Bonnans, Irit Sagi, Zena Werb. Targeting matrix metalloproteinases (MMP) for anti-metastatic therapy: Blocking active MMP9 abrogates metastatic niche formation and prevents metastatic seeding in a breast cancer model. [abstract]. In: Proceedings of the 106th Annual Meeting of the American Association for Cancer Research; 2015 Apr 18-22; Philadelphia, PA. Philadelphia (PA): AACR; Cancer Res 2015;75(15 Suppl):Abstract nr 4724. doi:10.1158/1538-7445.AM2015-4724</jats:p