Mutation in NADPH oxidase 3 (NOX3) impairs SHH signaling and increases cerebellar neural stem/progenitor cell proliferation.

Abnormalities in cerebellar structure and function may cause ataxia, a neurological dysfunction of motor coordination. In the course of the present study, we characterized a mutant mouse lineage with an ataxia-like phenotype. We localized the mutation on chromosome 17 and mapped it to position 1534 of the Nox3 gene, resulting in p.Asn64Tyr change. The primary defect observed in Nox3eqlb mice was increased proliferation of cerebellar granule cell precursors (GCPs). cDNA microarray comparing Nox3eqlb and BALB/c neonatal cerebellum revealed changes in the expression of genes involved in the control of cell proliferation. Nox3eqlb GCPs and NSC produce higher amounts of reactive oxygen species (ROS) and upregulate the expression of SHH target genes, such as Gli1-3 and Ccnd1 (CyclinD1). We hypothesize that this new mutation is responsible for an increase in proliferation via stimulation of the SHH pathway. We suggest this mutant mouse lineage as a new model to investigate the role of ROS in neuronal precursor cell proliferation.

Chronic granulomatous disease: why an inflammatory disease?

Chronic granulomatous disease is a primary immunodeficiency caused by mutations in the genes encoding subunits of the phagocytic NADPH oxidase system. Patients can present with severe, recurrent infections and noninfectious conditions. Among the latter, inflammatory manifestations are predominant, especially granulomas and colitis. In this article, we systematically review the possible mechanisms of hyperinflammation in this rare primary immunodeficiency condition and their correlations with clinical aspects.

Chronic granulomatous disease: why an inflammatory disease?

Chronic granulomatous disease is a primary immunodeficiency caused by mutations in the genes encoding subunits of the phagocytic NADPH oxidase system. Patients can present with severe, recurrent infections and noninfectious conditions. Among the latter, inflammatory manifestations are predominant, especially granulomas and colitis. In this article, we systematically review the possible mechanisms of hyperinflammation in this rare primary immunodeficiency condition and their correlations with clinical aspects.

Effect of staurosporine in the morphology and viability of cerebellar astrocytes: role of reactive oxygen species and NADPH oxidase.

Cell death implies morphological changes that may contribute to the progression of this process. In astrocytes, the mechanisms involving the cytoskeletal changes during cell death are not well explored. Although NADPH oxidase (NOX) has been described as being a critical factor in the production of ROS, not much information is available about the participation of NOX-derived ROS in the cell death of astrocytes and their role in the alterations of the cytoskeleton during the death of astrocytes. In this study, we have evaluated the participation of ROS in the death of cultured cerebellar astrocytes using staurosporine (St) as death inductor. We found that astrocytes express NOX1, NOX2, and NOX4. Also, St induced an early ROS production and NOX activation that participate in the death of astrocytes. These findings suggest that ROS produced by St is generated through NOX1 and NOX4. Finally, we showed that the reorganization of tubulin and actin induced by St is ROS independent and that St did not change the level of expression of these cytoskeletal proteins. We conclude that ROS produced by a NOX is required for cell death in astrocytes, but not for the morphological alterations induced by St.

NADPH phagocyte oxidase knockout mice control Trypanosoma cruzi proliferation, but develop circulatory collapse and succumb to infection.

(•)NO is considered to be a key macrophage-derived cytotoxic effector during Trypanosoma cruzi infection. On the other hand, the microbicidal properties of reactive oxygen species (ROS) are well recognized, but little importance has been attributed to them during in vivo infection with T. cruzi. In order to investigate the role of ROS in T. cruzi infection, mice deficient in NADPH phagocyte oxidase (gp91(phox) (-/-) or phox KO) were infected with Y strain of T. cruzi and the course of infection was followed. phox KO mice had similar parasitemia, similar tissue parasitism and similar levels of IFN-γ and TNF in serum and spleen cell culture supernatants, when compared to wild-type controls. However, all phox KO mice succumbed to infection between day 15 and 21 after inoculation with the parasite, while 60% of wild-type mice were alive 50 days after infection. Further investigation demonstrated increased serum levels of nitrite and nitrate (NOx) at day 15 of infection in phox KO animals, associated with a drop in blood pressure. Treatment with a NOS2 inhibitor corrected the blood pressure, implicating NOS2 in this phenomenon. We postulate that superoxide reacts with (•)NO in vivo, preventing blood pressure drops in wild type mice. Hence, whilst superoxide from phagocytes did not play a critical role in parasite control in the phox KO animals, its production would have an important protective effect against blood pressure decline during infection with T. cruzi.

Hyperresponsiveness of neutrophils from gp 91phox deficient patients to lipopolysaccharide and serum amyloid A.

We demonstrate here that neutrophils from chronic granulomatous disease (CGD) patients release larger amounts of interleukin-8 (IL-8) and tumor necrosis factor alpha (TNF-alpha) than neutrophils from control subjects. Incremental cytokine production was observed under both basal and stimulated conditions in neutrophils from two CGD (gp 91phox) patients. The basal production of IL-8 was over seven-fold greater in CGD patients. The two samples assayed showed 3- and 10-fold increases in TNF-alpha. Basically, the same magnitude of increment was observed in lypopolysaccharide (LPS) and serum amyloid A protein (SAA)-stimulated cells. We also found that the levels of SAA and IL-8 were higher in the serum of CGD patients than the levels found in the serum of healthy donors. The increased responsiveness of neutrophils from CGD patients may be closely related with a deficiency in the assembly of the nicotinamide adenine dinucleotide phosphate (NADPH)-oxidase enzyme system, or it may be due to a frequent inflammatory condition in these patients. In the latter case, the increased serum levels of systemic inflammatory factors, among them SAA, would contribute to the sustained accumulation and activation of phagocytes. Whatever the origin, the excessive production of cytokines may lead to inappropriate activation and tissue injury and even to increased susceptibility to invasive microorganisms, impairing the quality life of CGD patients.