Requirement for Slit-1 and Robo-2 in zonal segregation of olfactory sensory neuron axons in the main olfactory bulb.

The formation of precise stereotypic connections in sensory systems is critical for the ability to detect and process signals from the environment. In the olfactory system, olfactory sensory neurons (OSNs) project axons to spatially defined glomeruli within the olfactory bulb (OB). A spatial relationship exists between the location of OSNs within the olfactory epithelium (OE) and their glomerular targets along the dorsoventral axis in the OB. The molecular mechanisms underlying the zonal segregation of OSN axons along the dorsoventral axis of the OB are poorly understood. Using robo-2(-/-) (roundabout) and slit-1(-/-) mice, we examined the role of the Slit family of axon guidance cues in the targeting of OSN axons during development. We show that a subset of OSN axons that normally project to the dorsal region of the OB mistarget and form glomeruli in the ventral region in robo-2(-/-) and slit-1(-/-) mice. In addition, we show that the Slit receptor, Robo-2, is expressed in OSNs in a high dorsomedial to low ventrolateral gradient across the OE and that Slit-1 and Slit-3 are expressed in the ventral region of the OB. These results indicate that the dorsal-to-ventral segregation of OSN axons are not solely defined by the location of OSNs within the OE but also relies on axon guidance cues.

Quantitative assessment of human endometriotic tissue maintenance and regression in a noninvasive mouse model of endometriosis.

Endometriosis is a prevalent disease characterized by the estrogen-dependent ectopic growth of endometrial tissue. Most of the current medical therapies consist in inducing a hypoestrogenic state in patients, but these treatments are associated with severe side effects and high recurrence rates. The development of convenient and reliable endometriosis animal models would be instrumental to accelerate the emergence of new therapeutic alternatives. Recently, we developed an improved experimental model for endometriosis, relying on the infection of human endometrial fragments by an adenovirus carrying the green fluorescent protein. Following injection of fluorescent fragments into nude mice, the implantation and growth of endometriotic-like lesions could be followed noninvasively. In the present work, we demonstrate that this model can be used to quantify the size of fluorescent endometriotic lesions by in vivo imaging. To this end, we repeatedly measured lesion size over a 4-week period in mice supplemented or not with estradiol. The model was adequate to confirm previous results showing that estrogen is dispensable for the implantation phase of endometrial tissue, whereas it is required for lesion maintenance. As a proof of concept for inducing regression of established lesions, ganciclovir was used to treat animals implanted with human fluorescent endometrial fragments expressing thymidine kinase. A significant decrease in lesion size was observed by in vivo imaging in ganciclovir-treated mice. Together, the data indicate that the noninvasive animal model described here provides a tool for drug testing and/or gene target validation in endometriosis.

Development of a nonsurgical diagnostic tool for endometriosis based on the detection of endometrial leukocyte subsets and serum CA-125 levels.

OBJECTIVE: To determine whether the proportion of several leukocyte subsets is modulated in the endometrium of patients with endometriosis and, if yes, whether it can be used for diagnostic purposes. DESIGN: Case-control study. SETTING: Eight clinical institutions of the Montreal area. PATIENT(S): Women who underwent laparoscopy or laparotomy between 1997 and 2001, who had regular menstrual cycles and were not under hormone treatment for the previous 3 months were selected. This study included 368 women, 173 with surgically confirmed endometriosis and 195 controls with no surgical evidence of endometriosis. MAIN OUTCOME MEASURE(S): Cytometry analysis was used to measure the proportion of several leukocyte subsets among CD45(+) endometrial cells. RESULT(S): The proportion of CD3(+), CD16(+), CD3(-)HLADR(-), CD3(-)CD45RA(-), CD3(+)CD16(-), CD3(+)CD56(-), CD56(-)CD16(+), and CD16b(+) leukocytes was significantly altered in the endometrium of cases compared with controls. A multiple logistic regression model was adjusted with these endometrial leukocytes, serum CA-125 levels, risk factors, and confounders. The diagnostic performance of this predictive model was defined by a specificity of 95% and a sensitivity of 61%. Furthermore, the positive and negative predictive values were 91% and 75%, respectively. CONCLUSION(S): This predictive model represents a novel diagnostic tool to identify women with a high likelihood of suffering from endometriosis.

An improved mouse model for endometriosis allows noninvasive assessment of lesion implantation and development.

OBJECTIVE: To test whether fragments of human endometrium transduced with the green fluorescent protein (GFP) cDNA and transplanted into nude mice can be noninvasively visualized. DESIGN: A murine experimental model for human endometriosis. SETTING: A biotechnology company. ANIMAL(S): Ovariectomized nude mice. INTERVENTION(S): Whole fragments of human endometrium were transduced in vitro by adenoviral infection with the GFP cDNA before transplantation into nude mice. Animals were noninvasively and repeatedly imaged before lesion collection. MAIN OUTCOME MEASURE(S): Fluorescence of GFP-expressing human endometrial fragments was evaluated before transplantation into animals. Development of endometriotic lesions was monitored through direct visualization of fluorescent tissue in the living animal or through conventional dissection. RESULT(S): GFP gene transfer into whole endometrial fragments can be performed, and a high proportion of cells express the reporter gene. Fluorescent endometrial fragments implant in nude mice and form endometriotic-like lesions, which can be directly visualized through the skin of living mice using a simple imaging device. CONCLUSION(S): This improved mouse model allows noninvasive and dynamic studies of lesion implantation and development to be conducted. In addition to helping better understand the pathophysiology of the disease, this model represents a valuable preclinical tool for testing the efficacy of new drugs targeting endometriosis, which should ultimately accelerate their development phase.