Activation of Host Translational Control Pathways by a Viral Developmental Switch

In response to numerous signals, latent herpesvirus genomes abruptly switch their developmental program, aborting stable host–cell colonization in favor of productive viral replication that ultimately destroys the cell. To achieve a rapid gene expression transition, newly minted capped, polyadenylated viral mRNAs must engage and reprogram the cellular translational apparatus. While transcriptional responses of viral genomes undergoing lytic reactivation have been amply documented, roles for cellular translational control pathways in enabling the latent-lytic switch have not been described. Using PEL-derived B-cells naturally infected with KSHV as a model, we define efficient reactivation conditions and demonstrate that reactivation substantially changes the protein synthesis profile. New polypeptide synthesis correlates with 4E-BP1 translational repressor inactivation, nuclear PABP accumulation, eIF4F assembly, and phosphorylation of the cap-binding protein eIF4E by Mnk1. Significantly, inhibiting Mnk1 reduces accumulation of the critical viral transactivator RTA through a post-transcriptional mechanism, limiting downstream lytic protein production, and impairs reactivation efficiency. Thus, herpesvirus reactivation from latency activates the host cap-dependent translation machinery, illustrating the importance of translational regulation in implementing new developmental instructions that drastically alter cell fate

Solid organ transplants in HIV-infected patients.

There is a growing need for kidney and liver transplants in persons living with HIV. Fortunately, with the significant advances in antiretroviral therapy and management of opportunistic infections, HIV infection is no longer an absolute contraindication for solid organ transplantation. Data from several large prospective multi-center cohort studies have shown that solid organ transplantation in carefully selected HIV-infected individuals is safe. However, significant challenges have been identified including prevention of acute rejection, management of drug-drug interactions and treatment of recurrent viral hepatitis. This article reviews the selection criteria, outcomes, and special management considerations for HIV-infected patients undergoing liver or kidney transplantation

Brief Report: Parthenogenetic Embryonic Stem Cells are an Effective Cell Source for Therapeutic Liver Repopulation

Parthenogenesis is the development of an oocyte without fertilization. Mammalian parthenogenetic (PG) embryos are not viable, but can develop into blastocysts from which embryonic stem cells (ESCs) have been derived in mouse and human. PG ESCs are frequently homozygous for alleles encoding major histocompatibility complex (MHC) molecules. MHC homozygosity permits much more efficient immune matching than MHC heterozygosity found in conventional ESCs, making PG ESCs a promising cell source for cell therapies requiring no or little immune suppression. However, findings of restricted differentiation and proliferation of PG cells in developmental chimeras have cast doubt on the potential of PG ESC derivatives for organ regeneration. To address this uncertainty, we determined whether PG ESC derivatives are effective in rescuing mice with lethal liver failure due to deficiency of fumarylacetoacetate hydrolase (Fah). In developmental chimeras generated by injecting wild-type PG ESCs into Fah-deficient blastocysts, PG ESCs differentiated into hepatocytes that could repopulate the liver, provide normal liver function, and facilitate long-term survival of adult mice. Moreover, after transplantation into adult Fah-deficient mice, PG ESC-derived hepatocytes efficiently engrafted and proliferated, leading to high-level liver repopulation. Our results show that--despite the absence of a paternal genome--PG ESCs can form therapeutically effective hepatocytes

Surgical complications in 275 HIV-infected liver and/or kidney transplantation recipients

BackgroundIn this report, we examine the surgical safety and complications (SC) among 125 liver (L) and 150 kidney (K) HIV+ transplantation (TX) recipients in a prospective nonrandomized U.S. multicenter trial.MethodsSubjects were required to have CD4+ T-cell counts >200/100 cells/mm3 (K/L) and undetectable plasma HIV-1 RNA (Viral Load [VL]) (K) or expected posttransplantation suppression (L). Impact of SCs (N ≥ 7) was evaluated by use of the proportional hazards models. Baseline morbidity predictors for SCs (N ≥ 7) were assessed in univariate proportional hazards models.ResultsAt median 2.7 (interquartile range 1.9-4.1) and 2.3 (1.0-3.7) years after TX, 3-month and 1-year graft survival were [K] 96% (95% CI 91%-98%) and 91% (95% CI 85%-94%) and [L] 91% (95% CI 85%-95%) and 77% (95% CI 69%-84%), respectively. A total of 14 K and 28 L graft losses occurred in the first year; 6 K and 11 L were in the first 3 months. A total of 26 (17%) K and 43 (34%) L experienced 29 and 62 SCs, respectively. In the liver multivariate model, re-exploration was marginally associated (hazard ratio [HR] 2.8; 95% CI 1.0-8.4; P = .06) with increased risk of graft loss, whereas a greater MELD score before transplantation (HR 1.07 per point increase; 95% CI: 1.01-1.14; P = .02), and detectable viral load before TX (HR 3.6; 95% CI 0.9-14.6; P = .07) was associated with an increased risk of wound infections/dehiscence.ConclusionThe rates and outcomes of surgical complications are similar to what has been observed in the non-HIV setting in carefully selected HIV-infected liver and kidney TX recipients

Solid Organ Transplants in HIV-Infected Patients

There is a growing need for kidney and liver transplants in persons living with HIV. Fortunately, with the significant advances in antiretroviral therapy and management of opportunistic infections, HIV infection is no longer an absolute contraindication for solid organ transplantation. Data from several large prospective multi-center cohort studies have shown that solid organ transplantation in carefully selected HIV-infected individuals is safe. However, significant challenges have been identified including prevention of acute rejection, management of drug-drug interactions and treatment of recurrent viral hepatitis. This article reviews the selection criteria, outcomes, and special management considerations for HIV-infected patients undergoing liver or kidney transplantation