Differences in nuclear signaling by leukemia inhibitory factor and interferon-gamma: the role of STAT proteins in regulating vasoactive intestinal peptide gene expression.

To investigate the importance of STAT protein activation in leukemia inhibitory factor (LIF)-mediated induction of neuropeptide gene transcription, we compared signaling to the 180-bp cytokine response element (CyRE) in the vasoactive intestinal peptide (VIP) promoter by interferon-gamma (IFN-gamma) and LIF. We show that LIF and IFN-gamma activate STAT proteins but only LIF activates VIP gene transcription. Thus STAT activation is not sufficient for VIP transcriptional activation. In a CyRE reporter plasmid, in which the STAT site has been deleted, LIF, but not IFN-gamma, activates transcription, indicating that sequences within the CyRE distinct from the STAT site are important to LIF-mediated transcriptional activation. The CyRE does not mediate transcriptional activation to LIF in a non-VIPergic cell line, suggesting that cell-specific factors exist which are permissive for cytokine-dependent regulation of gene expression. Human and mouse sequences are highly conserved in the region of the CyRE, consistent with the functional importance of multiple regions of the CyRE. These findings show that regions within the CyRE distinct from the STAT site are important to the LIF-dependent regulation of VIP gene expression and enable the CyRE to respond in a cell-specific and cytokine-specific manner.

C/EBP-related sites in addition to a STAT site are necessary for ciliary neurotrophic factor-leukemia inhibitory factor-dependent transcriptional activation by the vasoactive intestinal peptide cytokine response element.

The neuropoietic cytokines ciliary neurotrophic factor (CNTF) and leukemia inhibitory factor (LIF) regulate VIP gene expression through a cytokine response element (CyRE) which interacts with members of the STAT transcription factor family. The CyRE STAT site is, however, insufficient to mediate full transcriptional activation by CNTF/LIF, suggesting that other sequences and nuclear proteins are also important. As C/EBP proteins participate in the transcriptional effects of the related cytokine, interleukin-6, we investigated the role of possible C/EBP-binding sites in the response of the VIP CyRE to CNTF/LIF. Using DNase I footprinting, transactivation studies, DNA mobility shift assays, and mutational analysis, three sites within the VIP CyRE were identified as C/EBP-related binding sites and shown to be important to CNTF/LIF-mediated transcriptional activation. The CyRE C/EBP-related sites interact with nuclear proteins from the human neuroblastoma cell line, NBFL, including a novel, protein synthesis-dependent, nuclear protein complex, induced by CNTF treatment. These nuclear proteins are not, however, recognized by antisera to known C/EBP proteins. Therefore, other nuclear proteins regulated by independent pathways act in concert with the JAK-STAT pathway to mediate CNTF/LIF regulation of VIP gene expression through the CyRE.

STAT proteins participate in the regulation of the vasoactive intestinal peptide gene by the ciliary neurotrophic factor family of cytokines.

Ciliary neurotrophic factor (CNTF) and leukemia inhibitory factor (LIF) are members of a family of neuropoietic cytokines that have a broad range of actions on many different neuronal populations. In cultured sympathetic neurons, CNTF and LIF induce transcription of the VIP and other neuropeptide genes as part of a program of differentiation. To gain insight into the nuclear events involved in cytokine-mediated activation of the neuropeptide genes involved in neuronal differentiation, we have investigated the mechanisms of transcriptional activation of the vasoactive intestinal peptide (VIP) gene by the CNTF family of cytokines. In the neuroblastoma cell line NBFL, CNTF, LIF, and a related cytokine, oncostatin-M, activate VIP gene transcription through a 180-base pair cytokine response element (CyRE). Deletion analysis of the VIP CyRE showed that multiple regions within the 180 base-pairs are important for cytokine-mediated transcriptional activation of the VIP gene. To one of these regions within the CyRE, cytokine treatment induces binding of a protein complex composed of members of the signal transducers and activators of transcription (STAT) transcription factor family. Mutation of this STAT-binding site attenuates cytokine-mediated transcriptional activation. LIF treatment of primary sympathetic neurons also induced binding of a STAT-containing protein complex to the VIP CyRE. Thus, activation of STAT transcription factors contributes to the induction of the VIp gene by the CNTF family of cytokines and may be involved in cytokine-mediated differentiation of sympathetic neurons.

Susceptibility of Periplaneta brunnea (Dictyoptera: Blattidae) to the nematode Steinernema carpocapsae (Rhabditida: Steinernematidae).

Brown cockroaches, Periplaneta brunnea Burmeister, were exposed to increasing population densities of the entomogenous nematode, Steinernema carpocapsae (Weiser), All Strains. A total of 160 adult cockroaches were used, 40 for each of four treatments: 0, 3,000, 30,000, and 300,000 infective juveniles added to 50 cm3 of sand. Population densities of 30,000 and 300,000 infective juveniles per 50 cm3 sand were the most effective treatments, killing 55% of the P. brunnea. The highest population density of nematodes, 300,000 infective juveniles per 50 cm3 sand, killed 93% of the P. brunnea, and produced a more rapid mortality when compared with other population densities.

False-positive reactions in the latex agglutination test for Cryptococcus neoformans antigen.

The latex agglutination test for Cryptococcus neoformans antigen is a simple and rapid procedure for the diagnosis of cryptococcal meningitis. Although the test is sensitive, care must be taken to prevent contamination of the sample, which may result in false-positive reactions. It was discovered in our laboratory that immersion of a platinum wire inoculating loop into a sample of cerebrospinal fluid prior to testing introduced interfering substances leading to nonspecific agglutination. After further studies, it was determined that trace amounts of surface condensation (syneresis fluid) from agar, either added to the cerebrospinal fluid or adhering to the loop, were the probable source of contamination. It is suggested that the latex agglutination test for C. neoformans antigen be performed prior to culture or on a separate sample.

Mass flea outbreak at a child care facility: case report.

Cat fleas, Ctenocephalides felis Bouchet, were collected at a Mississippi child care facility after reports of large numbers of adult fleas occurring on children and personnel. One building yielded 161 (99 percent) of the fleas collected. Urticarial lesions due to flea bites occurred on the legs of six children. Flea presence was due to cats occupying the crawl space. Fleas were eradicated by eliminating entry of cats and using residual insecticides throughout the facility.