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Cortical GABAergic interneurons are divided into various subtypes, with each subtype contributing to rich variety and fine details of inhibition. Despite the functional importance of each interneuron subtype, the molecular mechanisms that contribute to sorting them to their appropriate positions within the cortex remain unclear. Here, we show that the chemokine receptor CXCR4 regulates the regional and layer-specific distribution of interneuron subtypes. We removed Cxcr4 specifically in a subset of interneurons at a specific mouse embryonic developmental stage and analyzed the number of interneurons and their laminar distribution in 9 representative cortical regions comprehensively in adults. We found that the number of Cxcr4-deleted calretinin- and that of neuropeptide Y-expressing interneurons were reduced in most caudomedial and lateral cortical regions, respectively, and also in superficial layers. In addition, Cxcr4-deleted somatostatin-expressing interneurons showed a reduction in the number of superficial layers in certain cortical regions but of deep layers in others. These findings suggest that CXCR4 is required for proper regional and laminar distribution in a wider interneuron subpopulation than previously thought and may regulate the establishment of functional cortical circuitry in certain cortical regions and layers.

Background: Studies suggest that cytomegalovirus (CMV) infection exacerbates ulcerative colitis (UC) refractory to immunosuppressive therapies. Early and accurate diagnosis of CMV infection is important for the treatment of UC. We evaluated the usefulness of quantitative real-time polymerase chain reaction (PCR) for detecting CMV infection in inflamed colonic mucosa of patients with UC refractory to immunosuppressive therapies., Methods: From 2003 to 2006, 30 patients (mean age: 41 +/- 18 years; 14 men, 16 women) with UC refractory to immunosuppressive therapies were enrolled in the study. We evaluated CMV infection by CMV antigenemia, histologic examination, and quantitative real-time PCR for CMV using colonic mucosa and investigated the clinical outcomes of antiviral therapy., Results: CMV-DNA was detected only in the inflamed colonic mucosa in 17 (56.7%) of 30 patients. Of the 17 CMV-DNA-positive patients, 4 were positive for CMV antigenemia or inclusion bodies on histologic examination; of the 13 CMV-DNA-negative patients none was positive for CMV antigenemia or inclusion bodies. Of the 17 CMV-DNA-positive patients, 12 (70.6%) were treated with ganciclovir for 2 weeks and 10 patients went into remission. Two other patients required colectomy after antiviral therapy. In contrast, of the 13 CMV-DNA-negative patients 12 (92.3%) achieved remission after intensifying their immunosuppressive therapies., Conclusions: Quantitative real-time PCR assay for detecting CMV-DNA is useful for early, accurate diagnosis of CMV infection in patients with UC refractory to immunosuppressive therapies, enabling prompt and appropriate treatment.