Leveraging interacting signaling pathways to robustly improve the quality and yield of human pluripotent stem cell-derived hepatoblasts and hepatocytes.

Pluripotent stem cell (PSC)-derived hepatocyte-like cells (HLCs) have shown great potential as an alternative to primary human hepatocytes (PHHs) for in vitro modeling. Several differentiation protocols have been described to direct PSCs toward the hepatic fate. Here, by leveraging recent knowledge of the signaling pathways involved in liver development, we describe a robust, scalable protocol that allowed us to consistently generate high-quality bipotent human hepatoblasts and HLCs from both embryonic stem cells and induced PSC (iPSCs).

Preclinical Assessment of Mutant Human TRIM5α as an Anti-HIV-1 Transgene.

Current HIV-1 gene therapy approaches aim at stopping the viral life cycle at its earliest steps, such as entry or immediate postentry events. Among the most widely adopted strategies are CCR5 downregulation/knockout and the use of broadly neutralizing antibodies. However, the long-term efficacy and side effects are still unclear.

The V86M mutation in HIV-1 capsid confers resistance to TRIM5α by abrogation of cyclophilin A-dependent restriction and enhancement of viral nuclear import.

Background: HIV-1 is inhibited early after entry into cells expressing some simian orthologues of the tripartite motif protein family member TRIM5α. Mutants of the human orthologue (TRIM5αhu) can also provide protection against HIV-1. The host protein cyclophilin A (CypA) binds incoming HIV-1 capsid (CA) proteins and enhances early stages of HIV-1 replication by unknown mechanisms.

A novel aminoacid determinant of HIV-1 restriction in the TRIM5α variable 1 region isolated in a random mutagenic screen.

Human-derived antiretroviral transgenes are of great biomedical interest and are actively pursued. HIV-1 is efficiently inhibited at post-entry, pre-integration replication stages by point mutations in the variable region 1 (v1) of the human restriction factor TRIM5α. Here we use a mutated megaprimer approach to create a mutant library of TRIM5αHu v1 and to isolate a mutation at Gly330 (G330E) that inhibits transduction of an HIV-1 vector as efficiently as the previously described mutants at positions Arg332 and Arg335.

Murine double minute 2 as a modulator of retroviral restrictions mediated by TRIM5alpha.

In human cells, endogenous TRIM5alpha strongly inhibits N-tropic strains of murine leukemia virus (N-MLV) but does not target the closely related B-MLV. We have used a shRNA-based loss-of-function screen to isolate factors other than TRIM5alpha involved in the restriction of N-MLV. In one of the isolated clones, the shRNA expressed was found to target the murine double minute-2 mRNA.