Interaction of CED-4 with CED-3 and CED-9: a molecular framework for cell death.

Previous genetic studies of the nematode Caenorhabditis elegans identified three important components of the cell death machinery. CED-3 and CED-4 function to kill cells, whereas CED-9 protects cells from death. Here CED-9 and its mammalian homolog Bcl-xL (a member of the Bcl-2 family of cell death regulators) were both found to interact with and inhibit the function of CED-4. In addition, analysis revealed that CED-4 can simultaneously interact with CED-3 and its mammalian counterparts interleukin-1beta-converting enzyme (ICE) and FLICE. Thus, CED-4 plays a central role in the cell death pathway, biochemically linking CED-9 and the Bcl-2 family to CED-3 and the ICE family of pro-apoptotic cysteine proteases.

Consumer and carer perspectives in the development of a mental health research, treatment and teaching facility: A thematic analysis.

WHAT IS KNOWN ON THE SUBJECT?: Around the world, recovery has become a focus in mental health policy. The participation of people accessing mental health services (consumers) and carers of such individuals in decision-making related to services forms part of this recovery orientation and studies suggest positive outcomes following such participation. However, little is known about consumer and carer desires at the earliest stages of development of new services. WHAT THIS PAPER ADDS TO EXISTING KNOWLEDGE?: Consumers and carers desire changes to how mental health services are provided. Many factors affect consumer and carer experiences, including language use, physical design of spaces, accessibility, consideration of individual needs, practical help and how well care is continued from hospital to community settings. Carers may feel sidelined in treatment and be distressed as a result. They wish to be respected and involved in recovery. Consumers and carers wish for focus on broader health, with care taken to address physical health, psychological needs, social needs and treatment of the whole person rather than just an illness. WHAT ARE THE IMPLICATIONS FOR PRACTICE?: Consumers and carers desire partnership with professionals in recovery. Tokenistic participation should be avoided. Flexibility in how services are provided and less formality may help engage consumers and carers. Specifically, professionals may help by linking consumers and carers to services that address practical needs. Professionals should communicate with carers to draw on their expertise about the individual accessing the mental health service and help carers understand how they can assist the individual's recovery. ABSTRACT: Introduction Recovery-oriented mental health policies recognize consumer and carer participation in service decision-making as essential, but little is known about the views of these individuals in the earliest stages of service development. Aim This study sought consumer and carer perspectives addressing the establishment of a mental health research, treatment and teaching facility in their region. Methods Two 2-hr focus groups were conducted, with separate groups held for mental health consumers (n = 9) and carers (n = 9), respectively. Discussions pertained to mental health literacy, gaps in current services, desires for an ideal facility (in terms of physical design and services offered) and what would help in recovery. Results Inductive thematic analysis was used to generate three themes: care outside of consultations, carer involvement in recovery and holistic approaches to mental health care. Consumers desired a facility that could cater to individual needs. Carers felt excluded in recovery and unable to provide effective support. Both groups preferred holistic approaches to mental health, expressing ambivalence towards medication and hospitalization. Discussion Consumers and carers have many needs that conventional practices may not meet. Implications for practice They have clear desires for equal partnership in recovery and for transformation of conventional treatment methods.

Pneumocystis carinii mutations associated with sulfa and sulfone prophylaxis failures in AIDS patients.

BACKGROUND: Failures of prophylaxis against Pneumocystis carinii pneumonia (PCP) in AIDS patients do occur, but no evidence for drug resistance has yet been presented. OBJECTIVE: To determine whether mutations in the sulfa and sulfone drug target are associated with failure of prophylaxis using a sulfa-containing agent. METHODS: Portions of the gene for P. carinii dihydropteroate synthase (DHPS), the sulfa and sulfone target, from 27 patients (20 of whom had AIDS) diagnosed with PCP between 1976 and 1997 were amplified using polymerase chain reaction and sequenced. Seven of the 27 patients (all of whom had AIDS) were receiving sulfa or sulfone drugs as prophylaxis for PCP. RESULTS: Mutations were found at only two amino-acid positions and were significantly more common in patients who received sulfa/sulfone prophylaxis. Mutations were observed in five (71%) out of seven isolates from AIDS patients receiving sulfa/sulfone as prophylaxis compared with only two (15%) out of 13 specimens from AIDS patients who did not (P = 0.022). No mutations were seen in isolates from seven non-HIV-infected patients, none of whom were on prophylaxis. Mutations were only observed in specimens obtained in 1995-1997. CONCLUSIONS: Mutations in two amino-acid positions were significantly more common in AIDS patients with PCP who failed sulfa/sulfone prophylaxis. These amino acids appeared to be directly involved in both substrate and sulfa binding, based on homology to the Escherichia coli DHPS crystal structure. Thus, the results were consistent with the possibility that mutations in the P. carinii DHPS are responsible for some of the failures of sulfa/sulfone prophylaxis in AIDS patients.

Human immunodeficiency virus type 1 (HIV-1)-induced GRO-alpha production stimulates HIV-1 replication in macrophages and T lymphocytes.

We examined the early effects of infection by CCR5-using (R5 human immunodeficiency virus [HIV]) and CXCR4-using (X4 HIV) strains of HIV type 1 (HIV-1) on chemokine production by primary human monocyte-derived macrophages (MDM). While R5 HIV, but not X4 HIV, replicated in MDM, we found that the production of the C-X-C chemokine growth-regulated oncogene alpha (GRO-alpha) was markedly stimulated by X4 HIV and, to a much lesser extent, by R5 HIV. HIV-1 gp120 engagement of CXCR4 initiated the stimulation of GRO-alpha production, an effect blocked by antibodies to CXCR4. GRO-alpha then fed back and stimulated HIV-1 replication in both MDM and lymphocytes, and antibodies that neutralize GRO-alpha or CXCR2 (the receptor for GRO-alpha) markedly reduced viral replication in MDM and peripheral blood mononuclear cells. Therefore, activation of MDM by HIV-1 gp120 engagement of CXCR4 initiates an autocrine-paracrine loop that may be important in disease progression after the emergence of X4 HIV.

TNF-alpha inhibits HIV-1 replication in peripheral blood monocytes and alveolar macrophages by inducing the production of RANTES and decreasing C-C chemokine receptor 5 (CCR5) expression.

The pathogenesis of HIV-1 infection is influenced by the immunoregulatory responses of the host. Macrophages present in the lymphoid tissue are susceptible to infection with HIV-1, but are relatively resistant to its cytopathic effects and serve as a reservoir for the virus during the course of disease. Previous investigators have demonstrated that increased serum levels of TNF-alpha contribute to the clinical symptoms of AIDS and that TNF-alpha stimulates the production of HIV-1 in chronically infected lymphocytic and monocytic cell lines by increasing HIV-1 gene expression. Although previous studies have suggested that TNF-alpha may increase HIV-1 infection of primary human mononuclear cells, some recent studies have indicated that TNF-alpha suppresses HIV-1 infection of macrophages. We now demonstrate that TNF-alpha suppresses HIV-1 replication in freshly infected peripheral blood monocytes (PBM) and alveolar macrophages (AM) in a dose-dependent manner. As TNF-alpha has been shown to increase the production of C-C chemokine receptor (CCR5)-binding chemokines under certain circumstances, we hypothesized that TNF-alpha inhibits HIV-1 replication by increasing the expression of these HIV-suppressive factors. We now show that TNF-alpha treatment of PBM and AM increases the production of the C-C chemokine, RANTES. Immunodepletion of RANTES alone or in combination with macrophage inflammatory protein-1alpha and -1beta block the ability of TNF-alpha to suppress viral replication in PBM and AM. In addition, we found that TNF-alpha treatment reduces CCR5 expression on PBM and AM. These findings suggest that TNF-alpha plays a significant role in inhibiting monocytotropic strains of HIV-1 by two distinct, but complementary, mechanisms.

Dihydropteroate synthase polymorphisms in Pneumocystis carinii.

Sulfa drugs are widely used in the treatment and prophylaxis of Pneumocystis carinii pneumonia. The nucleotide sequences of the sulfa target enzyme, dihydropteroate synthase (DHPS), differed substantially in human-, rat-, and mouse-derived P. carinii. Sequence variation also existed in the DHPSs from human-derived isolates. Six nucleotide changes were found in 6 human isolates; each was nonsynonymous and resulted in an amino acid change. Several of these changes were in highly conserved regions and are similar to those that cause sulfa resistance in other organisms. These data suggest that the human-derived P. carinii DHPS may be evolving under positive selective pressure from sulfa drugs.

GLI-2 modulates retroviral gene expression.

GLI proteins are involved in the development of mice, humans, zebrafish, Caenorhabditis elegans, Xenopus, and Drosophila. While these zinc finger-containing proteins bind to TG-rich promoter elements and are known to regulate gene expression in C. elegans and Drosophila, mechanistic understanding of how regulation is mediated through naturally occurring transcriptional promoters is lacking. One isoform of human GLI-2 appears to be identical to a factor previously called Tax helper protein (THP), thus named due to its ability to interact with a TG-rich element in the human T-lymphotropic virus type 1 (HTLV-1) enhancer thought to mediate transcriptional stimulation by the Tax protein of HTLV-1. We now demonstrate that, working through its TG-rich binding site and adjacent elements, GLI-2/THP actually suppresses gene expression driven by the HTLV-1 promoter. GLI-2/THP has no effect on the HTLV-2 promoter, activates expression from the promoters of human immunodeficiency virus types 1 and (HIV-1 and -2), and stimulates HIV-1 replication. Both effective suppression and activation of gene expression and viral replication require the first of the five zinc fingers, which is not necessary for DNA binding, to be intact. Thus, not only can GLI-2/THP either activate or suppress gene expression, depending on the promoter, but the same domain (first zinc finger) mediates both effects. These findings suggest a role for GLI-2 in retroviral gene regulation and shed further light on the mechanisms by which GLI proteins regulate naturally occurring promoters.

Interleukin-8 stimulates human immunodeficiency virus type 1 replication and is a potential new target for antiretroviral therapy.

Production of the C-X-C chemokines interleukin-8 (IL-8) and growth-regulated oncogene alpha (GRO-alpha) in macrophages is stimulated by exposure to human immunodeficiency virus type 1 (HIV-1). We have demonstrated previously that GRO-alpha then stimulates HIV-1 replication in both T lymphocytes and macrophages. Here we demonstrate that IL-8 also stimulates HIV-1 replication in macrophages and T lymphocytes. We further show that increased levels of IL-8 are present in the lymphoid tissue of patients with AIDS. In addition, we demonstrate that compounds which inhibit the actions of IL-8 and GRO-alpha via their receptors, CXCR1 and CXCR2, also inhibit HIV-1 replication in both T lymphocytes and macrophages, indicating potential therapeutic uses for these compounds in HIV-1 infection and AIDS.

Human GLI-2 is a tat activation response element-independent Tat cofactor.

Zinc finger-containing GLI proteins are involved in the development of Caenorhabditis elegans, Xenopus, Drosophila, zebrafish, mice, and humans. In this study, we show that an isoform of human GLI-2 strongly synergizes with the Tat transactivating proteins of human immunodeficiency virus types 1 and 2 (HIV-1 and -2) and markedly stimulates viral replication. GLI-2 also synergizes with the previously described Tat cofactor cyclin T1 to stimulate Tat function. Surprisingly, GLI-2/Tat synergy is not dependent on either a typical GLI DNA binding site or an intact Tat activation response element but does require an intact TATA box. Thus, GLI-2/Tat synergy results from a mechanism of action which is novel both for a GLI protein and for a Tat cofactor. These findings link the GLI family of transcriptional and developmental regulatory proteins to Tat function and HIV replication.