Roles of Cytokines in the Temporal Changes of Microglial Membrane Currents and Neuronal Excitability and Synaptic Efficacy in ATP-Induced Cortical Injury Model.

Cytokines are important neuroinflammatory modulators in neurodegenerative brain disorders including traumatic brain injury (TBI) and stroke. However, their temporal effects on the physiological properties of microglia and neurons during the recovery period have been unclear. Here, using an ATP-induced cortical injury model, we characterized selective effects of ATP injection compared to needle-control. In the damaged region, the fluorescent intensity of CX3CR1-GFP (+) cells, as well as the cell density, was increased and the maturation of newborn BrdU (+) cells continued until 28 day-post-injection (dpi) of ATP. The excitability and synaptic E/I balance of neurons and the inward and outward membrane currents of microglia were increased at 3 dpi, when expressions of tumor necrosis factor (TNF)-α/interleukin (IL)-1ß and IL-10/IL-4 were also enhanced. These changes of both cells at 3 dpi were mostly decayed at 7 dpi and were suppressed by any of IL-10, IL-4, suramin (P2 receptor inhibitor) and 4-AP (K+ channel blocker). Acute ATP application alone induced only small effects from both naïve neurons and microglial cells in brain slice. However, TNF-α alone effectively increased the excitability of naïve neurons, which was blocked by suramin or 4-AP. TNF-α and IL-1ß increased and decreased membrane currents of naïve microglia, respectively. Our results suggest that ATP and TNF-α dominantly induce the physiological activities of 3 dpi neurons and microglia, and IL-10 effectively suppresses such changes of both activated cells in K+ channel- and P2 receptor-dependent manner, while IL-4 suppresses neurons preferentially.

Neuronal growth regulator 1-deficient mice show increased adiposity and decreased muscle mass.

BACKGROUND: Neuronal growth regulator 1 (NEGR1) is a glycosylphosphatidylinositol-anchored membrane protein that mediates neural cell communication and synapse formation. Multiple genome-wide association studies have reported that variations in NEGR1 are associated with human body weight control. Recently, we found that NEGR1 is involved in intracellular cholesterol trafficking, suggesting that it performs a non-central nervous system (CNS) function associated with human obesity. METHODS: We compared peripheral tissues such as the adipose, liver, and skeletal muscle tissues of Negr1-/- and Negr1+/+ (wild-type [WT]) C57BL/6 mice (n = 5-14). Intracellular lipid content was measured, and lipid accumulation was visualized by staining tissue cross-sections with lipid-specific stains. Muscle capacity of the WT and Negr1-/- mice was determined by performing a treadmill endurance test, and muscle fiber size was examined. Plasma glucose and insulin levels were measured, and glucose and insulin tolerance tests were performed. RESULTS: The Negr1-/- mice showed a significant increase in fat mass (~1.5-fold increase in the epididymal white adipose tissue, p = 0.000002), with abnormally enlarged adipose cells, compared with the WT mice. Primary adipocytes of the Negr1-/- mice contained enlarged cytosolic lipid droplets (p = 0.049). Moreover, these mice showed significant hepatic lipid accumulation (~2.3-fold increase, p = 0.043). Although the Negr1-/- mice did not show a significant change in plasma lipoprotein level, they showed a >1.3-fold increase in a serum glucose (p = 0.0002) and insulin (p = 0.016) levels. Moreover, the Negr1-/- mice showed decreased muscle capacity, as indicated by a decrease in muscle mass (p = 0.000003). CONCLUSION: These results indicate that NEGR1 deficiency induces abnormal fat deposition in various peripheral cells, especially fat and liver tissue cells, and suggest that NEGR1 is a potential molecular target for designing anti-obesity drugs to regulate body weight both centrally and peripherally.

The new obesity-associated protein, neuronal growth regulator 1 (NEGR1), is implicated in Niemann-Pick disease Type C (NPC2)-mediated cholesterol trafficking.

Neuronal growth regulator 1 (NEGR1) is a newly identified raft-associated protein, which has recently been spotlighted as a new locus related to human obesity. Niemann-Pick disease Type C2 (NPC2) protein functions as a key player in the intracellular cholesterol trafficking, and its defect is linked to a fatal human neurodegenerative disease, NPC. In this study, we identified that NEGR1 interacts with NPC2 and increases its protein stability. Ectopically expressed NEGR1 proteins relieved an abnormal cholesterol accumulation in endosomal compartments. Importantly, NEGR1-defective mouse embryonic fibroblast cells exhibit increased cholesterol levels and triglyceride contents. These findings provide the first insight into the role of NEGR1 in intracellular cholesterol homeostasis, possibly explaining the missing link between NEGR1 with human obesity.

Efficacy and safety of metronidazole for pulmonary multidrug-resistant tuberculosis.

Pulmonary lesions from active tuberculosis patients are thought to contain persistent, nonreplicating bacilli that arise from hypoxic stress. Metronidazole, approved for anaerobic infections, has antituberculosis activity against anoxic bacilli in vitro and in some animal models and may target persistent, nonreplicating bacilli. In this double-blind, placebo-controlled trial, pulmonary multidrug-resistant tuberculosis subjects were randomly assigned to receive metronidazole (500 mg thrice daily) or placebo for 8 weeks in addition to an individualized background regimen. Outcomes were measured radiologically (change on high-resolution computed tomography [HRCT]), microbiologically (time to sputum smear and culture conversion), and clinically (status 6 months after stopping therapy). Enrollment was stopped early due to excessive peripheral neuropathies in the metronidazole arm. Among 35 randomized subjects, 31 (15 metronidazole, 16 placebo) were included in the modified intent-to-treat analysis. There were no significant differences by arm in improvement of HRCT lesions from baseline to 2 or 6 months. More subjects in the metronidazole arm converted their sputum smear (P = 0.04) and liquid culture (P = 0.04) to negative at 1 month, but these differences were lost by 2 months. Overall, 81% showed clinical success 6 months after stopping therapy, with no differences by arm. However, 8/16 (50%) of subjects in the metronidazole group and 2/17 (12%) of those in the placebo group developed peripheral neuropathy. Subjects who received metronidazole were 4.3-fold (95% confidence interval [CI], 1.1 to 17.1) more likely to develop peripheral neuropathies than subjects who received placebo. Metronidazole may have increased early sputum smear and culture conversion but was too neurotoxic to use over the longer term. Newer nitroimidazoles with both aerobic and anaerobic activity, now in clinical trials, may increase the sterilizing potency of future treatment regimens.

Activation of lipopolysaccharide-TLR4 signaling accelerates the ototoxic potential of cisplatin in mice.

Dysfunction in immune surveillance during anticancer chemotherapy of patients often causes weakness of the host defense system and a subsequent increase in microbial infections. However, the deterioration of organ-specific function related to microbial challenges in cisplatin-treated patients has not yet been elucidated. In this study, we investigated cisplatin-induced TLR4 expression and its binding to LPS in mouse cochlear tissues and the effect of this interaction on hearing function. Cisplatin increased the transcriptional and translational expression of TLR4 in the cochlear tissues, organ of Corti explants, and HEI-OC1 cells. Furthermore, cisplatin increased the interaction between TLR4 and its microbial ligand LPS, thereby upregulating the production of proinflammatory cytokines, such as TNF-α, IL-1ß, and IL-6, via NF-κB activation. In C57BL/6 mice, the combined injection of cisplatin and LPS caused severe hearing impairment compared with that in the control, cisplatin-alone, or LPS-alone groups, whereas this hearing dysfunction was completely suppressed in both TLR4 mutant and knockout mice. These results suggest that hearing function can be easily damaged by increased TLR expression and microbial infections due to the weakened host defense systems of cancer patients receiving therapy comprising three to six cycles of cisplatin alone or cisplatin combined with other chemotherapeutic agents. Moreover, such damage can occur even though patients may not experience ototoxic levels of cumulative cisplatin concentration.

A case of a ruptured pheochromocytoma with an intratumoral aneurysm managed by coil embolization.

Although the spontaneous rupture of adrenal pheochromocytoma is rare, it can be lethal because it can induce serious changes in the circulation. We describe a 32 year old man with bilateral pheochromocyroma presenting as abdominal pain. In the emergency room, an abdominal MRI showed an aneurysmal vessel in the right adrenal mass and accompanying hemorrhage around the tumor capsule. The bleeding site was found by transfemoral abdominal angiography. Coil embolization was done in the bleeding vessels, specifically branches of the right adrenal artery. The hemorrhage was successfully controlled and vital signs of the patient were restored. Following emergency care, biochemical and imaging studies showed compatible findings of a bilateral adrenal pheochromocytoma. Postoperative histologic findings confirmed these observations. A ruptured pheochromocytoma should be considered as a cause of acute abdomen in cases of a concomitant adrenal mass. Intratumoral aneurysmal bleeding may be a cause of ruptured tumor, and careful angiographic intervention will help to ensure safe control of bleeding in such an emergency situation, even in cases of bilateral tumor.