No abstract

No abstract

This study characterizes the interaction of murine macrophage nuclear proteins with the tumor necrosis factor alpha (TNF-a) promoter. Gel retardation and methylation interference assays showed that stimulation of TNF-aL gene transcription in peritoneal exudate macrophages was accompanied by induction of DNAbinding proteins that recognized with different affinities four elements related to the KB consensus motif and a Y-box motif. We suggest that the basal level of TNF-a expression in macrophages is due to the binding of a constitutive form of NF-KB, present at low levels in nuclei from resting thioglycolate exudate peritoneal macrophages, to some if not all of the KB motifs; we postulate that this constitutive form contains only the 50-kilodalton (kDa) DNA-binding protein subunits of NF-KB, not the 65-kDa protein subunits (P. Baeuerle and D. Baltimore, Genes Dev. 3:1689-1698). Agents such as glucocorticoids, which decrease TNF-c transcription, diminished the basal level of nuclear NF-KB. Stimulation of TNF-a transcription in macrophages by lipopolysaccharide, gamma interferon, or cycloheximide led to an increased content of nuclear NF-KB. This induced factor represents a different form of NF-KB, since it generated protein-DNA complexes of slower mobility; we propose that this induced form of NF-KB contains both the 50-and 65-kDa protein subunits, the latter ones being necessary to bind NF-KB to its cytoplasmic inhibitor in uninduced cells (Baeuerle and Baltimore, Genes Dev., 1989). In resting cells, this inducible form of NF-KB was indeed detectable in the cytosol after deoxycholate treatment. UV cross-linking experiments and gel retardation assays indicated that the inducible form of NF-KB is in a higher-order complex with other proteins.

hormonally regulated. That a proper balance between cell death and survival-promoting proteins is critical to achieve Transgenic mice expressing high levels of the BclxL or this physiological apoptotic wave at an early stage of Bcl2 proteins in the male germinal cells show a highly testicular germinal cell differentiation is substantiated by abnormal adult spermatogenesis accompanied by the finding of a comparable syndrome in mice defective sterility. This appears to result from the prevention of in the bax gene (Knudson et al., 1995). This early an early and massive wave of apoptosis in the testis, apoptotic wave of germ cells during establishment of which occurs among germinal cells during the first spermatogenesis may be required to maintain a proper round of spermatogenesis. In contrast, sporadic cell number ratio between maturing germ cells and Sertoli apoptosis among spermatogonia, which occurs in nor-cells. An intricate relationship involving a constant modumal adult testis, is not prevented in adult transgenic lation of activity and exchange of differentiation signals mice. The physiological early apoptotic wave in the indeed exists between these two cell types (reviewed in testis is coincident, in timing and localization, with a Jegou, 1993) from the first stage of spermatogenesis, and temporary high expression of the apoptosis-promoting its perturbation may extend to the life-long process of protein Bax, which disappears at sexual maturity. mature spermatogenesis. The critical role played by the intracellular balance, probably hormonally controlled, of the BclxL and Bax proteins (Bcl2 is apparently not expressed in normal Results mouse testis) in this early apoptotic wave is shown byMale transgenic mice expressing Bcl2 or the occurrence of a comparable testicular syndrome in overexpressing BclxL in their germinal cells are mice defective in the bax gene. The apoptotic wave sterile and display marked alterations in the late appears necessary for normal mature spermatogenesis stages of spermatogenesis to develop, probably because it maintains a critical cellMice bearing a human bcl2 or a human bclx transgene number ratio between some germinal cell stages and placed under the control of the promoter of the murine Sertoli cells, whose normal functions and differentihousekeeping phosphoglycerate kinase-1 (pgk-1) gene ation involve an elaborate network of communication.were generated. One male and four female founders Keywords: apoptosis/germinal cells/spermatogenesis/ bearing a bcl2 transgene were obtained. The male (T41) transgenic was sterile and one of the females (T56) showed a lack of vaginal opening at sexual maturity. The ovaries of this founder female were, however, functional, since, when grafted onto ovariectomized normal female mice, they

To investigate the relationship of TNFα levels to Plasmodium falciparum (PF) infection, plasma TNFα concentrations were measured in Pakistani adults and children with mild, severe, cerebral and chronic falciparum malaria and healthy (control) subjects. The initial geometric mean plasma concentrations of TNFα in adult patients with severe malaria (187.6 pg/mL) were significantly higher than mild malaria patients (87.1 pg/mL, P < 0.001). TNFα levels were not correlated to parasite density, cerebral malaria, young age, hypoglycemia or fatal outcome; however, they were associated with severe anemia, and hepatic and kidney dysfunction. TNFα levels were not significantly increased in 16 patients with hyperparasitemia and were significantly elevated (P < 0.02) in chronic malaria patients as compared to control subjects. TNFα levels were elevated independently in patients with anemia, hypoglycemia (P < 0.001, P < 0.05), and hepatic and kidney (P < 0.001 each) dysfunction. In this study, high TNFα levels were associated with several manifestations of severe malaria and were not specific to cerebral malaria and hyperparasitemia.