NF-κB activation mediates crystal translocation and interstitial inflammation in adenine overload nephropathy

Adenine overload promotes intratubular crystal precipitation and interstitial nephritis. We showed recently that these abnormalities are strongly attenuated in mice knockout for Toll-like receptors-2, -4, MyD88, ASC, or caspase-1. We now investigated whether NF-κB activation also plays a pathogenic role in this model. Adult male Munich-Wistar rats were distributed among three groups: C (n = 17), receiving standard chow; ADE (n = 17), given adenine in the chow at 0.7% for 1 wk and 0.5% for 2 wk; and ADE + pyrrolidine dithiocarbamate (PDTC; n = 14), receiving adenine as above and the NF-κB inhibitor PDTC (120 mg•kg-1•day-1 in the drinking water). After 3 wk, widespread crystal deposition was seen in tubular lumina and in the renal interstitium, along with granuloma formation, collagen accumulation, intense tubulointerstitial proliferation, and increased interstitial expression of inflammatory mediators. Part of the crystals were segregated from tubular lumina by a newly formed cell layer and, at more advanced stages, appeared to be extruded to the interstitium. p65 nuclear translocation and IKK-α increased abundance indicated activation of the NF-κB system. PDTC treatment prevented p65 migration and normalized IKK-α, limited crystal shift to the interstitium, and strongly attenuated interstitial fibrosis/inflammation. These findings indicate that the complex inflammatory phenomena associated with this model depend, at least in part, on NF-κB activation, and suggest that the NF-κB system may become a therapeutic target in the treatment of chronic kidney disease.

Norepinephrine activates NF-κB transcription factor in cultured rat pineal gland

AIMS: The circadian rhythm in mammalian pineal melatonin secretion is modulated by norepinephrine (NE) released at night. NE interaction with β1-adrenoceptors activates PKA that phosphorylates the transcription factor CREB, leading to the transcription and translation of the arylalkylamine-N-acetyltransferase (AANAT) enzyme. Several studies have reported the interplay between CREB and the nuclear factor-κB (NF-κB) and a circadian rhythm for this transcription factor was recently described in the rat pineal gland. In this work we studied a direct effect of NE on NF-κB activation and the role played by this factor on melatonin synthesis and Aanat transcription and activity. MAIN METHODS: Cultured rat pineal glands were incubated in the presence of two different NF-κB inhibitors, pyrrolidine-dithiocarbamate or sodium salicylate, and stimulated with NE. Melatonin content was quantified by HPLC with electrochemical detection. AANAT activity was measured by a radiometric assay and the expression of Aanat mRNA was analyzed by real-time PCR. Gel shift assay was performed to study the NF-κB activation in cultured rat pineal glands stimulated by NE. KEY FINDINGS: Our results showed that the p50/p50 homodimer of NF-κB is activated by NE and that it has a role in melatonin synthesis, acting on Aanat transcription and activity. SIGNIFICANCE: Here we present evidence that NF-κB is an important transcription factor that acts, directly or indirectly, on Aanat transcription and activity leading to a modulation of melatonin synthesis. NE plays a role in the translocation of NF-κB p50/p50 homodimer to the nucleus of pinealocytes, thus probably influencing the nocturnal pineal melatonin synthesis

Monoclonal B-cell lymphocytosis (MBL), CD4(+)/CD8(weak) T-cell large granular lymphocytic leukemia (T-LGL leukemia) and monoclonal gammopathy of unknown significance (MGUS): molecular and flow cytometry characterization of three concomitant hematological disorders

The diagnosis of T-cell large granular lymphocytic leukemia in association with other B-cell disorders is uncommon but not unknown. However, the concomitant presence of three hematological diseases is extraordinarily rare. We report an 88-year-old male patient with three simultaneous clonal disorders, that is, CD4+/CD8(weak) T-cell large granular lymphocytic leukemia, monoclonal gammopathy of unknown significance and monoclonal B-cell lymphocytosis. The patient has only minimal complaints and has no anemia, neutropenia or thrombocytopenia. Lymphadenopathy and hepatosplenomegaly were not present. The three disorders were characterized by flow cytometry analysis, and the clonality of the T-cell large granular lymphocytic leukemia was confirmed by polymerase chain reaction. Interestingly, the patient has different B-cell clones, given that plasma cells of monoclonal gammopathy of unknown significance exhibited a kappa light-chain restriction population and, on the other hand, B-lymphocytes of monoclonal B-cell lymphocytosis exhibited a lambda light-chain restriction population. This finding does not support the antigen-driven hypothesis for the development of multi-compartment diseases, but suggests that T-cell large granular lymphocytic expansion might represent a direct antitumor immunological response to both B-cell and plasma-cell aberrant populations, as part of the immune surveillance against malignant neoplasms.

Influence of the dopaminergic system, CREB, and transcription factor-κB on cocaine neurotoxicity

Cocaine is a widely used drug and its abuse is associated with physical, psychiatric and social problems. Abnormalities in newborns have been demonstrated to be due to the toxic effects of cocaine during fetal development. The mechanism by which cocaine causes neurological damage is complex and involves interactions of the drug with several neurotransmitter systems, such as the increase of extracellular levels of dopamine and free radicals, and modulation of transcription factors. The aim of this review was to evaluate the importance of the dopaminergic system and the participation of inflammatory signaling in cocaine neurotoxicity. Our study showed that cocaine activates the transcription factors NF-κB and CREB, which regulate genes involved in cellular death. GBR 12909 (an inhibitor of dopamine reuptake), lidocaine (a local anesthetic), and dopamine did not activate NF-κB in the same way as cocaine. However, the attenuation of NF-κB activity after the pretreatment of the cells with SCH 23390, a D1 receptor antagonist, suggests that the activation of NF-κB by cocaine is, at least partially, due to activation of D1 receptors. NF-κB seems to have a protective role in these cells because its inhibition increased cellular death caused by cocaine. The increase in BDNF (brain-derived neurotrophic factor) mRNA can also be related to the protective role of both CREB and NF-κB transcription factors. An understanding of the mechanisms by which cocaine induces cell death in the brain will contribute to the development of new therapies for drug abusers, which can help to slow down the progress of degenerative processes.