Primary cilia mediate early life programming of adiposity through lysosomal regulation in the developing mouse hypothalamus.

Hypothalamic neurons including proopiomelanocortin (POMC)-producing neurons regulate body weights. The non-motile primary cilium is a critical sensory organelle on the cell surface. An association between ciliary defects and obesity has been suggested, but the underlying mechanisms are not fully understood. Here we show that inhibition of ciliogenesis in POMC-expressing developing hypothalamic neurons, by depleting ciliogenic genes IFT88 and KIF3A, leads to adulthood obesity in mice. In contrast, adult-onset ciliary dysgenesis in POMC neurons causes no significant change in adiposity. In developing POMC neurons, abnormal cilia formation disrupts axonal projections through impaired lysosomal protein degradation. Notably, maternal nutrition and postnatal leptin surge have a profound impact on ciliogenesis in the hypothalamus of neonatal mice; through these effects they critically modulate the organization of hypothalamic feeding circuits. Our findings reveal a mechanism of early life programming of adult adiposity, which is mediated by primary cilia in developing hypothalamic neurons.

Cellular source of hypothalamic macrophage accumulation in diet-induced obesity.

BACKGROUND: Obese mice on a high-fat diet (HFD) display signs of inflammation in the hypothalamic arcuate nucleus (ARC), a critical area for controlling systemic energy metabolism. This has been suggested as a key mechanism of obesity-associated hypothalamic dysfunction. We reported earlier that bone marrow-derived macrophages accumulate in the ARC to sustain hypothalamic inflammation upon chronic exposure to an HFD. However, the mechanism underlying hypothalamic macrophage accumulation has remained unclear. METHODS: We investigated whether circulating monocytes or myeloid precursors contribute to hypothalamic macrophage expansion during chronic HFD feeding. To trace circulating myeloid cells, we generated mice that express green fluorescent protein (GFP) in their lysozyme M-expressing myeloid cells (LysMGFP mice). We conducted parabiosis and bone marrow transplantation experiments using these animals. Mice received an HFD for 12 or 30 weeks and were then sacrificed to analyze LysMGFP cells in the hypothalamus. Hypothalamic vascular permeability in the HFD-fed obese mice was also tested by examining the extravascular leakage of Evans blue and fluorescence-labeled albumin. The timing of LysMGFP cell entry to the hypothalamus during development was also evaluated. RESULTS: Our parabiosis and bone marrow transplantation experiments revealed a significant infiltration of circulating LysMGFP cells into the liver, skeletal muscle, choroid plexus, and leptomeninges but not in the hypothalamic ARC during chronic HFD feeding, despite increased hypothalamic vascular permeability. These results suggested that the recruitment of circulating monocytes is not a major mechanism for maintaining and expanding the hypothalamic macrophage population in diet-induced obesity. We demonstrated instead that LysMGFP cells infiltrate the hypothalamus during its development. LysMGFP cells appeared in the hypothalamic area from the late embryonic period. This cellular pool suddenly increased immediately after birth, peaked at the postnatal second week, and adopted an adult pattern of distribution after weaning. CONCLUSIONS: Bone marrow-derived macrophages mostly populate the hypothalamus in early postnatal life and may maintain their pool without significant recruitment of circulating monocytes throughout life, even under conditions of chronic HFD feeding.

Gemcitabine, etoposide, cisplatin, and dexamethasone in patients with refractory or relapsed non-Hodgkin's lymphoma.

BACKGROUND/AIMS: To date, an effective salvage chemotherapy regimen for the treatment of refractory or relapsing non-Hodgkin's lymphoma (NHL) has not been discovered. This study was conducted to evaluate the efficacy and safety of gemcitabine, etoposide, cisplatin, and dexamethasone in relapsed or refractory NHL patients. METHODS: All patients had histologically proven relapsed or refractory NHL. Treatments consisted of gemcitabine 700 mg/m(2) by continuous i.v. on days 1 and 8; etoposide 40 mg/m(2) by i.v. on days 1-4; cisplatin 60 mg/m(2) by i.v. on day 1; or dexamethasone 40 mg by i.v. on days 1-4 (GEPD) every 21 days. The primary end point was the patient response rate following two cycles of treatment. After two cycles, stem cells were harvested using mobilizing regimens (ESHAP or GEPD plus filgrastim), and this was followed by autologous stem cell transplantation or four additional cycles of GEPD. RESULTS: Between January 2005 and January 2006, 20 patients (13 males and 7 females) were enrolled in the study. The median age was 53 (range 16-75) years. The most common histology was diffuse large B-cell lymphoma (n=10). The median follow-up duration was 5.2 (range 1.0-16.0) months. After two cycles, the overall response rate was 50.0% (10/20), including two complete responses and eight partial responses. The dose-limiting toxicity was myelosuppression. Grade IV neutropenia and thrombocytopenia occurred in 13 (65.0%) and 6 patients (30.0%), respectively. The median number of CD34-positive cells collected was 6.0 (range, 2.8-11.6)x10(6)/kg. Of the 17 patients < 66 years of age, 4 (23.5%) proceeded to autologous stem cell transplantation. CONCLUSIONS: GEPD chemotherapy in patients with refractory or relapsed NHL was effective as a salvage therapy and helpful for stem cell harvest followed by autologous transplantation.