CSF1R inhibition with PLX5622 affects multiple immune cell compartments and induces tissue-specific metabolic effects in lean mice.

AIMS/HYPOTHESIS: Colony stimulating factor 1 (CSF1) promotes the proliferation, differentiation and survival of macrophages, which have been implicated in both beneficial and detrimental effects on glucose metabolism. However, the physiological role of CSF1 signalling in glucose homeostasis and the potential therapeutic implications of modulating this pathway are not known. We aimed to study the composition of tissue macrophages (and other immune cells) following CSF1 receptor (CSF1R) inhibition and elucidate the metabolic consequences of CSF1R inhibition. METHODS: We assessed immune cell populations in various organs by flow cytometry, and tissue-specific metabolic effects by hyperinsulinaemic-euglycaemic clamps and insulin secretion assays in mice fed a chow diet containing PLX5622 (a CSF1R inhibitor) or a control diet. RESULTS: CSF1R inhibition depleted macrophages in multiple tissues while simultaneously increasing eosinophils and group 2 innate lymphoid cells. These immunological changes were consistent across different organs and were sex independent and reversible after cessation of the PLX5622. CSF1R inhibition improved hepatic insulin sensitivity but concomitantly impaired insulin secretion. In healthy islets, we found a high frequency of IL-1ß+ islet macrophages. Their depletion by CSF1R inhibition led to downregulation of macrophage-related pathways and mediators of cytokine activity, including Nlrp3, suggesting IL-1ß as a candidate insulin secretagogue. Partial restoration of physiological insulin secretion was achieved by injecting recombinant IL-1ß prior to glucose stimulation in mice lacking macrophages. CONCLUSIONS/INTERPRETATION: Macrophages and macrophage-derived factors, such as IL-1ß, play an important role in physiological insulin secretion. A better understanding of the tissue-specific effects of CSF1R inhibition on immune cells and glucose homeostasis is crucial for the development of targeted immune-modulatory treatments in metabolic disease. DATA AVAILABILITY: The RNA-Seq dataset is available in the Gene Expression Omnibus (GEO) under the accession number GSE189434 ( http://www.ncbi.nlm.nih.gov/geo/query/acc.cgi?acc=GSE189434 ).

Protocol for isolation and spectral flow cytometry analysis of immune cells from the murine exocrine and endocrine pancreas.

Diabetes mellitus is a disease of the hormone-secreting endocrine pancreas. However, increasing evidence suggests that the exocrine pancreas is also involved in the pathogenesis of diabetes. In this protocol, we describe how to harvest both isolated islets and exocrine tissue from one mouse pancreas, followed by a detailed explanation of how to isolate and analyze immune cells using full-spectrum flow cytometry.

Targeting colonic macrophages improves glycemic control in high-fat diet-induced obesity.

The obesity epidemic continues to worsen worldwide. However, the mechanisms initiating glucose dysregulation in obesity remain poorly understood. We assessed the role that colonic macrophage subpopulations play in glucose homeostasis in mice fed a high-fat diet (HFD). Concurrent with glucose intolerance, pro-inflammatory/monocyte-derived colonic macrophages increased in mice fed a HFD. A link between macrophage numbers and glycemia was established by pharmacological dose-dependent ablation of macrophages. In particular, colon-specific macrophage depletion by intrarectal clodronate liposomes improved glucose tolerance, insulin sensitivity, and insulin secretion capacity. Colonic macrophage activation upon HFD was characterized by an interferon response and a change in mitochondrial metabolism, which converged in mTOR as a common regulator. Colon-specific mTOR inhibition reduced pro-inflammatory macrophages and ameliorated insulin secretion capacity, similar to colon-specific macrophage depletion, but did not affect insulin sensitivity. Thus, pharmacological targeting of colonic macrophages could become a potential therapy in obesity to improve glycemic control.

ß Cell-Specific Deletion of the IL-1 Receptor Antagonist Impairs ß Cell Proliferation and Insulin Secretion.

Interleukin-1 receptor antagonist (IL-1Ra) is elevated in the circulation during obesity and type 2 diabetes (T2D) but is decreased in islets from patients with T2D. The protective role of local IL-1Ra was investigated in pancreatic islet ß cell (ßIL-1Ra)-specific versus myeloid-cell (myeloIL-1Ra)-specific IL-1Ra knockout (KO) mice. Deletion of IL-1Ra in ß cells, but not in myeloid cells, resulted in diminished islet IL-1Ra expression. Myeloid cells were not the main source of circulating IL-1Ra in obesity. ßIL-1Ra KO mice had impaired insulin secretion, reduced ß cell proliferation, and decreased expression of islet proliferation genes, along with impaired glucose tolerance. The key cell-cycle regulator E2F1 partly reversed IL-1ß-mediated inhibition of potassium channel Kir6.2 expression and rescued impaired insulin secretion in IL-1Ra knockout islets. Our findings provide evidence for the importance of ß cell-derived IL-1Ra for the local defense of ß cells to maintain normal function and proliferation.

Leishmaniasis visceral: contribución a su control mediante el fortalecimiento del diagnóstico del reservorio canino en Posadas, Misiones, Argentina / Visceral leishmaniasis: control contribution by strengthening the diagnosis of dog reservoir in the city of Posadas, Misiones, Argentina

INTRODUCCION: La leishmaniasis visceral (LV) es una enfermedad emergente en Argentina. En 2006 se describió el primer caso autóctono en Posadas (Misiones), ciudad que se convirtió en epicentro de la LV.OBJETIVO: Determinar la prevalencia de la LV canica (LVC) y fortalecer su diagnóstico en Posadas.METODOS: Con un criterio entomológico, la ciudad de Posadas se dividió en islas de alta densidad (IAD) e islas de baja densidad (IBD) de flebótomos. Se seleccionó, de forma arbitraria y mediante imágenes satelitales, la manzana situada más al norte y más al sur de cada IAD e IBD. Se realizó un diseño observacional prospectivo, y se estudió a todos los perros de las manzanas seleccionadas. Se consideró un N inicial de 400 animales para detectar una diferencia de al menos 7% con una potencia de 0,90 y un nivel de 0,05 respecto de la prevalencia global supuesta del 20%. Se tomaron muestras de sangre, punción de ganglios linfáticos y raspado de piel. El estudio incluyó además un test serológico rápido (rK39 canino) y frotis de las muestras para búsqueda parasitológica, que se procesaron y evaluaron en el Instituto Municipal de Salud Animal de Posadas y en el Instituto Nacional de Parasitología Fatala Chabén.RESULTADOS: De los 182 animales evaluados, 33 fueron positivos para LVC, con una prevalencia global del 18,1%. En IAD la prevalencia fue 22% y en IBD, 13,4%. Los estudios parasitológicos fueron positivos en el 10% de los caninos en IAD y 1,2% en IBD. La LVC fue asintomática u oligosintomática, con una presentación más frecuente en IAD. La rK39 tuvo una sensibilidad del 90,3% y una especificidad del 98,9%.CONCLUSIONES: El análisis serológico con antígeno rK39 fue siempre más sensible que la búsqueda parasitológica para el diagnóstico. La LVC parece tener menor prevalencia en relación con estudios previos, quizás debido a diferentes medidas de control realizadas en el Municipio de Posadas.

INTRODUCCION: Visceral leishmanisis (VL) is an emerging disease in Argentina. The first autochthonous case was described in 2006 in a chld from Posadas (Misiones), the city which turned out to be the focus of VL.OBJECTIVE: To determine the prevalence of canine VL (CVL) and improve its diagnosis in Posadas.METHODS: According to entomological criteria, Posadas was divided in high density islands (HDI) and low density islands (LDI) of sandfly. Randomly and with satellite images, the northernmost and southernmost blocks of each HDI and LDI were selected. A prospective, experimental design was performed, studying all the dogs in the selected blocks. There was an initial sample of 400 animals to detect a difference of at least 7%, with a power of 0.90 and a level of 0.05, compared to the supposed prevalence of 20%. Blood samples were taken, with puncture of lymph nodes and skin scraping. The study also included a (canine rK39) rapid test for serological assessment adn sample smears for parasitological search. Samples were processed and evaluated in the Posadas institute of animal health (I.MU.S.A) and the Fatala Chabén National Institute of Parasitology.RESULTS: CVL was assessed in 33/182 animals with an overall prevalence of 18.1%. In HDI, the prevalence was 22%; in LDI, it was 13.4%. Parasitological studies were positive in 10% (HDI) and 1.2% (LDI). The CVL had a nonspecific clinical presentation; canines were asimptomatic or oligosymptomatic, with a higher trend in HDI. The rK39 had a sensitivity of 90.3% and a specificity of 98.9%.CONCLUSIONS: The antigen rK39 was always more sensitive than the search for parasites for the diagnosis of CVL. The disease appears to be less prevalent comapring to previous studies, perhaps due to different control measures performed in the Municipality of Posadas.

Leishmaniasis visceral: contribución a su control mediante el fortalecimiento del diagnóstico del reservorio canino en Posadas, Misiones, Argentina / Visceral leishmaniasis: control contribution by strengthening the diagnosis of dog reservoir in the city of Posadas, Misiones, Argentina

INTRODUCCION: La leishmaniasis visceral (LV) es una enfermedad emergente en Argentina. En 2006 se describió el primer caso autóctono en Posadas (Misiones), ciudad que se convirtió en epicentro de la LV.OBJETIVO: Determinar la prevalencia de la LV canica (LVC) y fortalecer su diagnóstico en Posadas.METODOS: Con un criterio entomológico, la ciudad de Posadas se dividió en islas de alta densidad (IAD) e islas de baja densidad (IBD) de flebótomos. Se seleccionó, de forma arbitraria y mediante imágenes satelitales, la manzana situada más al norte y más al sur de cada IAD e IBD. Se realizó un diseño observacional prospectivo, y se estudió a todos los perros de las manzanas seleccionadas. Se consideró un N inicial de 400 animales para detectar una diferencia de al menos 7% con una potencia de 0,90 y un nivel de 0,05 respecto de la prevalencia global supuesta del 20%. Se tomaron muestras de sangre, punción de ganglios linfáticos y raspado de piel. El estudio incluyó además un test serológico rápido (rK39 canino) y frotis de las muestras para búsqueda parasitológica, que se procesaron y evaluaron en el Instituto Municipal de Salud Animal de Posadas y en el Instituto Nacional de Parasitología Fatala Chabén.RESULTADOS: De los 182 animales evaluados, 33 fueron positivos para LVC, con una prevalencia global del 18,1%. En IAD la prevalencia fue 22% y en IBD, 13,4%. Los estudios parasitológicos fueron positivos en el 10% de los caninos en IAD y 1,2% en IBD. La LVC fue asintomática u oligosintomática, con una presentación más frecuente en IAD. La rK39 tuvo una sensibilidad del 90,3% y una especificidad del 98,9%.CONCLUSIONES: El análisis serológico con antígeno rK39 fue siempre más sensible que la búsqueda parasitológica para el diagnóstico. La LVC parece tener menor prevalencia en relación con estudios previos, quizás debido a diferentes medidas de control realizadas en el Municipio de Posadas.

INTRODUCCION: Visceral leishmanisis (VL) is an emerging disease in Argentina. The first autochthonous case was described in 2006 in a chld from Posadas (Misiones), the city which turned out to be the focus of VL.OBJECTIVE: To determine the prevalence of canine VL (CVL) and improve its diagnosis in Posadas.METHODS: According to entomological criteria, Posadas was divided in high density islands (HDI) and low density islands (LDI) of sandfly. Randomly and with satellite images, the northernmost and southernmost blocks of each HDI and LDI were selected. A prospective, experimental design was performed, studying all the dogs in the selected blocks. There was an initial sample of 400 animals to detect a difference of at least 7%, with a power of 0.90 and a level of 0.05, compared to the supposed prevalence of 20%. Blood samples were taken, with puncture of lymph nodes and skin scraping. The study also included a (canine rK39) rapid test for serological assessment adn sample smears for parasitological search. Samples were processed and evaluated in the Posadas institute of animal health (I.MU.S.A) and the Fatala Chabén National Institute of Parasitology.RESULTS: CVL was assessed in 33/182 animals with an overall prevalence of 18.1%. In HDI, the prevalence was 22%; in LDI, it was 13.4%. Parasitological studies were positive in 10% (HDI) and 1.2% (LDI). The CVL had a nonspecific clinical presentation; canines were asimptomatic or oligosymptomatic, with a higher trend in HDI. The rK39 had a sensitivity of 90.3% and a specificity of 98.9%.CONCLUSIONS: The antigen rK39 was always more sensitive than the search for parasites for the diagnosis of CVL. The disease appears to be less prevalent comapring to previous studies, perhaps due to different control measures performed in the Municipality of Posadas.