Sustained suppression of plasma HIV RNA is associated with an increase in the production of mitogen-induced MIP-1alpha and MIP-1beta

Effects of NO-Hybridization on the Immunomodulatory Properties of the HIV Protease Inhibitors Lopinavir and Ritonavir

HIV protease inhibitors (PIs) are antiretroviral agents, which have been found to also affect several cellular processes, such as inflammation and cell progression. In studies on non-steroidal, anti-inflammatory drugs, the addition of a nitric oxide (NO) moiety has been shown to both reduce their toxicity and enhance their pharmacological efficacy. Along this line of research, several derivatives of PIs have been synthesized by covalent attachment of NO moiety to the parental molecules. Previous work has indicated that NO-hybridization of the prototypical PI, Saquinavir leads to a derivative named Saquinavir-NO that while retaining the antiretroviral effect, acquires antitumoural and immunomodulatory properties along with reduced toxicity in vitro and in vivo. These data prompted us to evaluate the effects of NO-hybridization on two other PIs, Lopinavir and Ritonavir. The two NO-derivatives were compared head to head with their parental compounds on human primary peripheral blood mononuclear cells as well as on human primary macrophages. Lopinavir-NO and Lopinavir were also screened in an in vivo model of autoimmune hepatitis. Our results prove that Lopinavir-NO exerts markedly superior effects as compared to the parental compound both in vitro and in vivo. On the contrary, Ritonavir-NO effects overlapped those of Ritonavir. These data demonstrate that NO-hybridization of Lopinavir generates a derivative with significantly stronger immunomodulatory effects that are apparently related to an action of the compound on T-cell secretory capacity. Lopinavir-NO deserves additional studies for its possible use in T-cell-mediated autoimmune diseases including, but not limited to autoimmune hepatitis.

Increased Levels of Macrophage Inflammatory Proteins Result in Resistance to R5-Tropic HIV-1 in a Subset of Elite Controllers

Elite controllers (ECs) are a rare group of HIV seropositive individuals who are able to control viral replication without antiretroviral therapy. The mechanisms responsible for this phenotype, however, have not been fully elucidated. In this study, we examined CD4(+) T cell resistance to HIV in a cohort of elite controllers and explored transcriptional signatures associated with cellular resistance. We demonstrate that a subgroup of elite controllers possess CD4(+) T cells that are specifically resistant to R5-tropic HIV while remaining fully susceptible to X4-tropic and vesicular stomatitis virus G (VSV-G)-pseudotyped viruses. Transcriptome analysis revealed 17 genes that were differentially regulated in resistant elite controllers relative to healthy controls. Notably, the genes encoding macrophage inflammatory protein 1α (MIP-1α), CCL3 and CCL3L1, were found to be upregulated. The MIP-1α, MIP-1β, and RANTES chemokines are natural ligands of CCR5 and are known to interfere with HIV replication. For three elite controllers, we observed increased production of MIP-1α and/or MIP-1β at the protein level. The supernatant from resistant EC cells contained MIP-1α and MIP-1β and was sufficient to confer R5-tropic resistance to susceptible CD4(+) T cells. Additionally, this effect was reversed by using inhibitory anti-MIP antibodies. These results suggest that the T cells of these particular elite controllers may be naturally resistant to HIV infection by blocking R5-tropic viral entry.

IMPORTANCE

HIV is a pandemic health problem, and the majority of seropositive individuals will eventually progress to AIDS unless antiretroviral therapy (ART) is administered. However, rare patients, termed elite controllers, have a natural ability to control HIV infection in the absence of ART, but the mechanisms by which they achieve this phenotype have not been fully explored. This paper identifies one mechanism that may contribute to this natural resistance: some elite controllers have CD4(+) T cells that produce high levels of MIP chemokines, which block R5-tropic HIV entry. This mechanism could potentially be exploited to achieve a therapeutic effect in other HIV-seropositive individuals.

Saquinavir-NO inhibits S6 kinase activity, impairs secretion of the encephalytogenic cytokines interleukin-17 and interferon-gamma and ameliorates experimental autoimmune encephalomyelitis

NO-hybridization of the HIV protease inhibitor Saquinavir generates a new chemical entity named Saq-NO, that retains the anti-viral activity and exerts lower toxicity. We show that Saq-NO inhibited the generation of various cytokines in ConA-stimulated unfractionated murine spleen cells and rat lymph nodes stimulated with ConA as well as in purified CD4(+) T cells in vitro and reduced the circulating levels of cytokines in mice challenged with anti-CD3 antibody. Furthermore, Saq-NO reduced IL-17 and IFN-γ production in myelin basic protein (MBP)-specific cells isolated from rats immunized with MBP. These findings translated well into the in vivo setting as Saq-NO ameliorated the course of the disease in two preclinical models of multiple sclerosis. Our results demonstrate that Saq-NO exerts immunomodulatory effects that warrant studies on its application in autoimmune diseases.

Production of the HIV-suppressive chemokines CCL3/MIP-1alpha and CCL22/MDC is associated with more effective antiretroviral therapy in HIV-infected children

BACKGROUND

Certain CC chemokines including ligands for the HIV-1 coreceptor CCR5 are associated with suppression of HIV-1 infection. Whether the release of these chemokines from lymphocytes influences treatment outcome in children receiving antiretroviral therapy is not known.

METHODS

A study of 175 HIV-infected children in Rio de Janeiro, Brazil was conducted to compare clinical measures and HIV-suppressive chemokine release. Clinical measures including %CD4 T cells, viral loads, and antiretroviral drug-resistant mutations were obtained. Chemokine release was measured in cultures of peripheral blood mononuclear cells collected from 135 children before or after receiving therapy. Chemokine levels were compared between subject groups stratified according to clinical measures and treatment regimen (1-2, 3-4, or no antiretrovirals) extant at the time of cell sample collection.

RESULTS

Mean viral loads did not vary significantly between treatment groups although there were significant differences in %CD4 T cells. Virus from children taking 3-4 antiretrovirals had significantly more drug-resistant mutations than did virus from those receiving 1-2 drugs. Among antiretroviral-treated children, there was a significant direct relationship between %CD4 T cells and MIP-1alpha/CCL3 and macrophage-derived chemokine/CCL22 production. In addition, there was a significant inverse relationship between viral load and MIP-1alpha production in patients receiving 3-4 antiretrovirals. Greater recovery of %CD4 T cells after therapy was associated with higher MIP-1alpha and macrophage-derived chemokine production at baseline.

CONCLUSIONS

The production of HIV-suppressive chemokines is associated with better outcome in children receiving antiretroviral regimens in settings where drug-resistant mutations are prevalent. Such information may provide insights for the design of treatment strategies for pediatric HIV infection under similar circumstances.

Disturbed secretory capacity for macrophage inflammatory protein (MIP)-1 alpha and MIP-1 beta in progressive HIV infection

The protective role of beta-chemokines in HIV infection and disease remains controversial. Contradictory findings have been reported possibly as the result of different beta-chemokine detection methods. To test this, peripheral blood lymphocytes from treatment-naive HIV patients, patients on highly active antiretroviral therapy (HAART), and uninfected controls were assessed for intracellular beta-chemokine levels in comparison with levels of beta-chemokine secretion in culture supernatants. HIV patients had significantly higher intracellular levels of macrophages inflammatory protein (MIP)-1 alpha and MIP-1 beta than uninfected control subjects. In contrast, MIP-1 alpha and MIP-1 beta supernatant levels were significantly lower in HIV patients than in controls. Interestingly, both intracellular and supernatant levels of RANTES (regulated on activation, normal T cell expressed and secreted) were significantly increased in HIV patients. Prolonged (> 3 years) administration of HAART in HIV patients normalized the intracellular levels of MIP-1 beta and RANTES and restored the decreased supernatant levels of MIP-1 alpha and MIP-1 beta to levels observed among controls. Significant direct correlations observed between the intracellular and the supernatant levels of beta-chemokines in controls were lost in treatment-naive (except MIP-1 beta) and HAART-treated patients (except RANTES after 3 years of HAART). These data indicate that lymphocytes of HIV patients display a disrupted capacity to secrete the beta-chemokines MIP-1 alpha and MIP-1 beta, which may constitute a mechanism of immune dysfunction in progressive HIV infection. Furthermore, we demonstrated that the detection of beta-chemokines in HIV patients by different methods may indeed result in contradictory findings.

Down-regulation of CXCR-4 and CCR-5 expression by interferon-gamma is associated with inhibition of chemotaxis and human immunodeficiency virus (HIV) replication but not HIV entry into human monocytes

Alterations in the expression of CXCR4 and CCR5, the co-receptors for HIV entry, may be associated with susceptibility of monocytic cells to HIV infection. Interferon (IFN)-gamma has been shown to inhibit HIV replication in monocytic cells, but the molecular mechanism involved is not well understood. To determine if IFN-gamma regulates HIV replication by altering CXCR-4/CCR-5 expression and hence virus entry into monocytic cells, we investigated the effects of IFN-gamma on CXCR-4 and CCR-5 expression and its biological implications with respect to HIV entry, replication and chemotaxis towards the CXCR-4 and CCR-5 ligands SDF-1 and MIP-1alpha, respectively. IFN-gamma decreased CXCR-4 and CCR-5 expression on monocytes derived from HIV-negative adults, HIV-positive adults and HIV-negative cord blood. This down-regulation of chemokine receptor expression did not result in a corresponding change in mRNA expression but was associated with elevated levels of the endogenously produced chemokines SDF-1 and RANTES. Furthermore, IFN-gamma inhibited chemotaxis in response to SDF-1 and MIP-1alpha, inhibited HIV replication, but failed to inhibit virus entry in monocytic cells. These results suggest that although IFN-gamma-induced down-regulation of CXCR-4 and CCR-5 expression is associated with an inhibition of SDF-1-/MIP-1alpha-mediated chemotaxis, IFN-gamma-induced inhibition of HIV replication may be mediated at levels subsequent to the virus entry.

Lack of good correlation of serum CC-chemokine levels with human immunodeficiency virus-1 disease stage and response to treatment

Three CC-chemokines-MIP-1alpha (CCL3), MIP-1beta (CCL4), and RANTES (CCL5)-are natural ligands for the human immunodeficiency virus-1 (HIV-1) coreceptor CCR5. To determine correlations between CC-chemokines and HIV-1 disease stage or response to treatment, we examined serum levels of MIP-1alpha, MIP-1beta, and RANTES in 60 infected patients during 18 months while they were taking highly active antiretroviral therapy (HAART). Our results demonstrate that serum levels of MIP-1alpha and RANTES were increased in HIV-1-infected individuals compared with those in healthy controls. We found no significant differences among 4 clinical stages of HIV-1 infection in the serum levels of three CC-chemokines. Longitudinal HAART analyses revealed a pronounced decline in serum MIP-1alpha levels over time. We found no difference in this decline between HAART responders and nonresponders. These findings indicate that production of MIP-1alpha and RANTES changes during HIV-1 infection and treatment; however, our results suggest that serum levels of CC-chemokines should not be used as biomarkers for HIV-1 disease stage or response to treatment.

Surrogacy in antiviral drug development

The coming of age of molecular biology has resulted in an explosion in our understanding of the pathogenesis of virus related diseases. New pathogens have been identified and characterized as being responsible for old diseases. Empirical clinical evaluation of morbidity and mortality as outcome measures after a therapeutic intervention have started to give way to the use of an increasing number of surrogate markers. Using a combination of these markers, it is now possible to measure and monitor the pathogen as well as the host's response. Nowhere is this better exemplified in virology than in the field of AIDS. We have utilized the advances in pathogenesis and new antiretroviral drug development to: * develop a new class of drugs which block the entry of HIV-1 into cells. * develop a new approach for effectively delivering these drugs to those tissues in which most viral replication takes place. Over the last 10 years, our work has progressed from concept to clinical trial. Our laboratory based evaluation of the new molecules developed as well as our clinical evaluation of their safety and efficacy have had to respond and adapt to the rapid changes taking place in AIDS research. This paper discusses the problems encountered and the lessons learnt.

Changes in CCR5 and CXCR4 expression and beta-chemokine production in HIV-1-infected patients treated with highly active antiretroviral therapy

The effect of highly active antiretroviral therapy (HAART) on the expression of CCR5 and CXCR4 HIV coreceptors and the production of the beta-chemokines regulated upon activation, normal T-cell expressed and secreted (RANTES), macrophage inflammatory protein (MIP)-1alpha, and MIP-1beta has been investigated in 30 HIV-1-infected individuals during 12-36 months of therapy. CCR5 expression was increased in both CD4 + and CD8 + subsets, whereas CXCR4 expression was upregulated only in CD4 + cells. CCR5 levels normalized during 36 months of therapy and positively correlated with the levels of memory, CD95 +, and HLA-DR + T cells. In contrast, the frequency of CXCR4-expressing cells was not significantly modified by HAART, although a downregulation was observed early after starting treatment. CXCR4 levels were significantly associated with the frequencies of naive T cells and negatively correlated with plasma viral load, CD95, and HLA-DR expression. An increased production of both spontaneous and lectin-induced RANTES, MIP-1alpha, and MIP-1beta was found at baseline in HIV-infected individuals. The spontaneous beta-chemokines production was not modified by 12 months of HAART, although a significant reduction was seen during the first months of therapy. A transient decrease of lectin-stimulated RANTES production was also observed, whereas the reduction of lectin-induced MIP-1alpha persisted for up to 12 months of therapy. In contrast, MIP-1beta secreted by phytohemagglutinin antigen-stimulated peripheral blood mononuclear cells progressively increased during HAART. In conclusion, our data indicate a normalization of CCR5 but not CXCR4 expression during suppressive therapy and changes in beta-chemokine production that may play a part in dictating the efficiency of viral infection and consequently the disease course.

Human immunodeficiency virus type-1 and chemokines: beyond competition for common cellular receptors

The chemokines and their receptors have been receiving exceptional attention in recent years following the discoveries that some chemokines could specifically block human immunodeficiency virus type 1 (HIV-1) infection and that certain chemokine receptors were the long-sought coreceptors which, along with CD4, are required for the productive entry of HIV-1 and HIV-2 isolates. Several chemokine receptors or orphan chemokine receptor-like molecules can support the entry of various viral strains, but the clinical significance of the CXCR4 and CCR5 coreceptors appear to overshadow a critical role for any of the other coreceptors and all HIV-1 and HIV-2 strains best employ one or both of these coreceptors. Binding of the HIV-1 envelope glycoprotein gp120 subunit to CD4 and/or an appropriate chemokine receptor triggers conformational changes in the envelope glycoprotein oligomer that allow it to facilitate the fusion of the viral and host cell membranes. During these interactions, gp120 appears to be capable of inducing a variety of signaling events, all of which are still not defined in detail. In addition, the more recently observed dichotomous effects, of both inhibition and enhancement, that chemokines and their receptor signaling events elicit on the HIV-1 entry and replication processes has once again highlighted the intricate and complex balance of factors that govern the pathogenic process. Here, we will review and discuss these new observations summarizing the potential significance these processes may have in HIV-1 infection. Understanding the complexities and significance of the signaling processes that the chemokines and viral products induce may substantially enhance our understanding of HIV-1 pathogenesis, and perhaps facilitate the discovery of new ways for the prevention and treatment of HIV-1 disease.

CCR5 and CXCR4 expression on memory and naive T cells in HIV-1 infection and response to highly active antiretroviral therapy

OBJECTIVE

To measure CCR5 and CXCR4 chemokine receptor expression on CD4 and CD8 T cells in HIV-1 infection and to relate levels to the distribution of CD45RO memory and CD45RA-naive subsets, measures of disease activity, and response to highly active antiretroviral therapy (HAART).

DESIGN

Fourteen untreated HIV-1-infected patients, 18 patients at 3-to 4-weeks after beginning HAART, and 35 uninfected control subjects were studied.

METHODS

Four-color cytofluorometry with appropriate conjugated monoclonal antibodies (mAbs) was performed to define CD45RA and CD45RO subsets of CD4 and CD8 T cells and measure their expression of CCR5, CXCR4, and CD38.

RESULTS

HIV-1-infected patients had higher CCR5 levels and lower CXCR4 levels on CD4 and CD8 T cells and their CD45RO/CD45RA subsets than control subjects did. However, CCR5 elevation was statistically significant only for CD4 T cells and their subsets, and CXCR4 depression was significant for CD8 T cells and their subsets (and for CD4:CD45RO cells). The elevation of CCR5 and depression of CXCR4 were not due to shifts in CD45RO/CD45RA subset proportions but to upregulation or downregulation within the subsets. CCR5 elevation on CD4 T cells was significantly restored toward normal by HAART, but the CXCR4 depression was not. CCR5 expression but not CXCR4 expression correlated with other measures of immunodeficiency (CD4 T-cell levels), active infection (viral load), and cellular activation (CD38).

CONCLUSIONS

CCR5 elevation is a concomitant of immune activation and viral replication that occurs in HIV-1 infection, but the relation of CXCR4 depression to severity of infection, disease progression, and response to therapy remains undefined.

Higher macrophage inflammatory protein (MIP)-1alpha and MIP-1beta levels from CD8+ T cells are associated with asymptomatic HIV-1 infection

To test the hypothesis that beta-chemokine levels may be relevant to the control of HIV in vivo, we compared RANTES, MIP-1alpha, and MIP-1beta production from purified CD8(+) T cells from 81 HIV-infected subjects and from 28 uninfected donors. Asymptomatic HIV(+) subjects produced significantly higher levels of MIP-1alpha and MIP-1beta, but not RANTES, than uninfected donors or patients that progressed to AIDS. In contrast, beta chemokines in plasma were either nondetectable or showed no correlation with clinical status. The high beta-chemokine-mediated anti-HIV activity was against the macrophage tropic isolate HIV-1(BAL), with no demonstrable effect on the replication of the T-cell tropic HIV-1(IIIB). These findings suggest that constitutive beta-chemokine production may play an important role in the outcome of HIV-1 infection.

Highly active antiretroviral therapy normalizes the potential for MIP-1alpha production in HIV infection

DESIGN

The CC chemokines RANTES, MIP-1alpha and MIP-1beta are ligands for CCR5, which has been identified as the principal co-receptor for macrophage tropic strains of HIV-1. This study investigated whether the inducible levels of RANTES, MIP-1alpha and MIP-1beta produced by cultured whole blood samples related to different rates of progression of HIV infection and to the introduction of Nelfinavir-based highly active anti-retroviral therapy (HAART).

METHODS

Study subjects were HIV-positive and categorized as "slow progressors" (n= 8) or as "fast progressors" (n= 7); the latter group were treated with HAART. MIP-1alpha, MIP-1beta and RANTES production was determined using commercial ELISA kits.

RESULTS

The inducible production of MIP-1alpha by whole blood cells in culture was significantly depressed in patients starting therapy compared with "slow progressors" and "normal donors". The levels of MIP-1alpha significantly increased with therapy at 12 weeks compared with pre-HAART levels (P= O.05) and became comparable to that of "normals" and "slow progressors". Differences in the inducible levels of MIP-1beta and RANTES for the separate subject groups were not significant.

CONCLUSIONS

The increase in inducible MIP-1alpha production following HAART might suggest a role for the chemokines in HIV disease, either for monitoring the outcome of therapy of HIV disease, or as a direct therapeutic intervention.

Circulating levels and ex vivo production of beta-chemokines, interferon gamma, and interleukin 2 in advanced human immunodeficiency virus type 1 infection: the effect of protease inhibitor therapy

Cytokines and beta-chemokines play an important role in the complex interaction between HIV-1 and the immune system. We studied platelet-free plasma (PFP) levels and ex vivo production of cytokines and beta-chemokines at different HIV disease stages and the influence of potent protease inhibitor therapy on their production in late-stage patients. Mitogen-induced production of MIP-1alpha, MIP-1beta, and RANTES by PBMCs was higher in HIV-infected patients than in HIV-seronegative controls. Patients with late-stage HIV infection (CD4+ cells <50/microl) showed a higher production of MIP-1alpha and RANTES and lower plasma levels of IL-2 compared with HIV-positive patients at the intermediate stage (CD4+ cells >150/microl). Pretreatment RANTES production correlated negatively with CD4+ and CD8+ cell counts; also, MIP-1alpha production was inversely correlated with CD4+ cell counts. Among patients with a CD4+ cell count <50/microl, RANTES production before protease inhibitor treatment was inversely correlated with viral load. Late-stage patients with IL-2 production higher than 50 pg/ml before treatment showed a more impressive increase in CD4+ cell counts after protease inhibitor therapy. The production of MIP-1alpha, MIP-1beta, RANTES, and IFN-gamma was markedly reduced at 8 weeks and partially restored at 24 weeks after beginning protease inhibitor therapy. PFP levels of RANTES showed a concurrent decrease. Patients with more advanced HIV infection show a higher production of inflammatory cytokines, which is reduced by protease inhibitor therapy. Residual late-stage IL-2 producers may represent a subset of patients with a higher potential for immunologic reconstitution.