The striking emergence of an epidemic of HIV-related renal disease in patients with end-stage renal disease provided the rationale for the exploration of whether HIV-1 directly infects renal ...parenchymal cells. Renal glomerular and tubular epithelial cells contain HIV-1 mRNA and DNA, indicating infection by HIV-1. In addition, circularized viral DNA, a marker of recent nuclear import of full-length, reverse-transcribed RNA, was detected in the biopsies, suggesting active replication in renal tissue. Infiltrating infected leukocytes harbored more viral mRNA than renal epithelium. Identification of this novel reservoir suggests that effectively targeting the kidney with antiretrovirals may be critical for patients who are seropositive with renal disease. Thus, renal epithelium constitutes a unique and previously unrecognized cell target for HIV-1 infection.
Kidney disease is an important complication of HIV, particularly in minority populations. We describe the burden of chronic kidney disease among 1239 adults followed at an urban AIDS center, with an ...estimated prevalence of 15.5% (n = 192). Independent predictors of kidney disease included older age, black race, hepatitis C virus exposure, and lower CD4 cell count. These data suggest that chronic kidney disease remains a common complication of HIV infection in the era of antiretroviral therapy.
Kidney disease is an increasingly important complication of HIV.
To examine the incidence and predictors of acute renal failure before and after the introduction of HAART, and the impact of acute ...renal failure on in-hospital mortality in the post-HAART era.
Adults hospitalized in acute care hospitals in New York State during 1995 (pre-HAART) or 2003 (post-HAART) were identified from the state Planning and Research Cooperative System database. HIV status was defined by primary or secondary diagnosis code. The impact of HIV and HAART on the incidence of acute renal failure and mortality, and the impact of acute renal failure on mortality, was assessed using chi analysis and multivariate regression.
There were 52,580 HIV-infected patients discharged from hospital in 1995 and 25,114 in 2003. Compared with uninfected patients, HIV-infected patients had an increased incidence of acute renal failure in both the pre-HAART adjusted odds ratio (OR), 4.62; 95% confidence interval (CI), 4.30-4.95 and post-HAART eras (adjusted OR, 2.82; 95% CI, 2.66-2.99). In the post-HAART cohort, acute renal failure was associated with traditional predictors such as age, diabetes mellitus, and chronic kidney disease, as well as acute or chronic liver failure or hepatitis coinfection (P < 0.001 for all comparisons). Acute renal failure was associated with mortality among HIV-infected patients in the post-HAART era (OR, 5.83; 95% CI, 5.11-6.65).
Acute renal failure remains common among hospitalized patients with HIV and is associated with chronic kidney disease, liver disease, and increased mortality.
In collapsing focal segmental glomerulosclerosis (FSGS) of HIV-associated nephropathy (HIVAN), podocytes exhibit a high proliferation rate and loss of differentiation markers. We have found ...previously that the nef gene of HIV-1 is responsible for these changes. Here, we investigated the signaling pathways induced by Nef and its role in the pathogenesis of HIVAN. Using conditionally immortalized podocytes after differentiation, we found that infection of podocytes with nef increased Src kinase activity and signal transducer and activator of transcription 3 (Stat3) phosphorylation and activated the Ras-c-Raf-MAPK1,2 pathway. A dominant negative mutant of Src abolished the Nef effect, whereas inhibition of MAPK1,2 or dominant negative Stat3 reduced Nef effects partially. Reducing the expression of Nef with small interference RNA reversed the Nef effect. Mutation of Nef in the PxxP or R105R106 motifs diminished Nef signaling and the phenotypic changes in podocytes. Both phospho-MAPK1,2 and phospho-Stat3 staining increased in podocytes of kidneys from HIV-1 transgenic mice compared with their littermates and in podocytes of kidneys from HIVAN patients compared with HIV patients with non-HIVAN kidney diseases or non-HIV patients with idiopathic FSGS, classic FSGS, or minimal-change disease. These data suggest that Nef-induced activation of Stat3 and Ras-MAPK1,2 via Src-dependent pathways is responsible for podocyte proliferation and dedifferentiation, a characteristic finding in collapsing FSGS of HIVAN.
HIV-associated nephropathy is a late, not early, manifestation of HIV-1 infection.
Human immunodeficiency virus–associated nephropathy (HIVAN) can be the initial presentation of HIV-1 infection. As a ...result, many have assumed that HIVAN can occur at any point in the infection. This issue has important implications for appropriate therapy and, perhaps, for pathogenesis. Since the development of new case definitions for acquired immunodeficiency syndrome (AIDS) and better tools to assess infection, the relationship of HIVAN to the time of AIDS infection has not been addressed. In this study, we reassessed the stage of infection at the time of HIVAN diagnosis in 10 patients, and we reviewed all previously published cases applying the new case definitions to assess stage of infection.
HIVAN was confirmed by kidney biopsy in HIV seropositive patients with azotemia and/or proteinuria. CD4+ cell count and plasma HIV-1 RNA copy number were measured. We also reviewed all published cases of HIVAN to determine if AIDS-defining conditions, by current Centers for Disease Control definitions, were present in patients with biopsy-proven HIVAN.
Twenty HIV-1 seropositive patients with proteinuria and an elevated creatinine concentration were biopsied. HIVAN was the single most common cause of renal disease. CD4+ cell count was below 200/mm3 in all patients with HIVAN, fulfilling Centers for Disease Control criteria for an AIDS-defining condition. HIV-1 plasma RNA was detectable in all patients with HIVAN. In reviewing previous reports, an AIDS-defining condition was present in virtually all patients with HIVAN.
HIVAN develops late, not early, in the course of HIV-1 infection following the development of AIDS. This likely accounts for the poor prognosis noted in previous publications and has implications for pathogenesis. In addition, given the detectable viral RNA levels, highly active antiretroviral therapy is indicated in HIVAN. Highly active antiretroviral therapy may improve survival as well as alter the natural history of HIVAN.
Defensins in innate antiviral immunity Klotman, Mary E; Chang, Theresa L
Nature Reviews: Immunology,
200606, 2006-Jun, 2006-06-01, 20060601, Letnik:
6, Številka:
6
Journal Article
Recenzirano
Odprti dostop
Defensins are small antimicrobial peptides that are produced by leukocytes and epithelial cells, and that have an important role in innate immunity. Recent advances in understanding the mechanisms of ...the antiviral action(s) of defensins indicate that they have a dual role in antiviral defence, acting directly on the virion and on the host cell. This Review focuses on the antiviral activities and mechanisms of action of mammalian defensins, and on the clinical relevance of these activities. Understanding the complex function of defensins in innate immunity against viral infection has implications for the prevention and treatment of viral disease.
High levels of circular viral extrachromosomal DNA (E-DNA) are normally produced after infection with integration-competent and -incompetent lentiviruses. Although E-DNA has been shown to be ...transcriptionally active, it lasts for only a short time in replicating cells. Here, we report an integrase (IN)-defective lentiviral episomal vector in which insertion of the simian virus 40 (SV40) promoter, containing the origin of replication (ori), is associated with long-term expression and persistence of E-DNA in the presence of SV40 large T antigen (TAg) from 293T cells. 293 and 293T cell lines transduced with IN-competent lentiviral vectors expressing green fluorescent protein (GFP) or luciferase from the cytomegalovirus (CMV) or SV40 promoter gave similar levels of transduction and expression. In contrast, only transient reporter expression occurred when using the CMV IN-defective control vector in both 293 and 293T cells. However, reporter gene expression was maintained for more than 8 weeks in 293T, but not 293, cells transduced with the IN-defective lentiviral vector containing the SV40-ori promoter. Polymerase chain reaction for two-long terminal repeat (2LTR) extrachromosomal circular forms, a marker of lentiviral E-DNA, and fluorescence in situ hybridization analysis confirmed the persistence and episomal nature of circular E-DNA up to 60 days after transduction. Taken together, these results indicate that insertion of the SV40-ori promoter in a lentiviral vector contributes to long-term expression by promoting episomal replication when TAg is provided in trans. Lentiviral episomal vectors may serve as specific tools for therapeutic approaches to diseases, particularly those associated with episomal replication of DNA viruses including papillomaviruses, polyomaviruses, and herpesviruses.
HIV-associated nephropathy (HIVAN) is the most common cause of end-stage renal disease in persons with HIV/AIDS and is characterized by focal glomerulosclerosis and dysregulated renal tubular ...epithelial cell (RTEC) proliferation and apoptosis. HIV-1 viral protein r (Vpr) has been implicated in HIV-induced RTEC apoptosis but the mechanisms of Vpr-induced RTEC apoptosis are unknown. The aim of this study was therefore to determine the mechanisms of Vpr-induced apoptosis in RTEC.
Apoptosis and caspase activation were analyzed in human RTEC (HK2) after transduction with Vpr-expressing and control lentiviral vectors. Bax and BID were inhibited with lentiviral shRNA, and ERK activation was blocked with the MEK1,2 inhibitor, U0126.
Vpr induced apoptosis as indicated by caspase 3/7 activation, PARP-1 cleavage and mitochondrial injury. Vpr activated both caspases-8 and 9. Inhibition of Bax reduced Vpr-induced apoptosis, as reported in other cell types. Additionally, Vpr-induced cleavage of BID to tBID and suppression of BID expression prevented Vpr-induced apoptosis. Since sustained ERK activation can activate caspase-8 in some cell types, we studied the role of ERK in Vpr-induced caspase-8 activation. Vpr induced sustained ERK activation in HK2 cells and incubation with U0126 reduced Vpr-induced caspase-8 activation, BID cleavage and apoptosis. We detected phosphorylated ERK in RTEC in HIVAN biopsy specimens by immunohistochemistry.
These studies delineate a novel pathway of Vpr-induced apoptosis in RTEC, which is mediated by sustained ERK activation, resulting in caspase 8-mediated cleavage of BID to tBID, thereby facilitating Bax-mediated mitochondrial injury and apoptosis.
Lentiviral vectors have been shown to be good candidates for gene transfer protocols; however, prevention of insertional mutagenesis remains problematic. Here we report on the design of a ...conditionally replicating integrase (IN)-defective lentiviral-hybrid episomal vector in which the insertion of the SV40 promoter/origin of replication provides long-term persistence of the extrachromosomal DNA in the presence of the corresponding
trans-acting T antigen (Tag) for targeted suicide gene therapy. SV40-driven GFP expression from the IN-defective lentiviral-hybrid vector was sustained only in the Tag positive 293T cell line, while expression was transient in the parental Tag deficient cell line 293. Quantitative PCR for the 2-LTR circular forms indicated that the unintegrated forms remained stable in 293T for up to 56 days post-transduction, while they were undetectable in the cell line 293 after day 14. Transduction of 293T cells with the IN-defective lentiviral-hybrid episomal vector containing the thymidine kinase (TK) gene rendered the Tag expressing cells highly susceptible to ganciclovir (GCV) treatment, as opposed to the cells infected with the control vector or in Tag negative cells. These data suggest that conditionally replicating IN-defective lentiviral-hybrid episomal vectors could prove useful as vehicles for suicide gene therapy, in particular in cells transformed by SV40.
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