Two retroviruses packaged in one cell line can combined inhibit the replication of HIV-1 in TZM-bl cells

Efficacy Analysis of Combinatorial siRNAs against HIV Derived from One Double Hairpin RNA Precursor

Combinatorial small interfering RNA duplexes (siRNAs) have the potential to be a gene therapy against HIV-1, and some studies have reported that transient combinatorial siRNA expression represses HIV replication, but the effects of long-term siRNA expression on HIV replication have not been studied in detail. In this study, HIV-1 replication under the influence of stable combinatorial siRNA expression from a single RNA transcript was analyzed. First, a series of cassettes encoding short hairpin RNA (shRNA)/long hairpin RNA (lhRNA)/double long hairpins (dlhRNA) was constructed and subjected to an analysis of inhibitory efficacy. Next, an optimized dlhRNA encoding cassette was selected and inserted into lentiviral delivery vector FG12. Transient dlhRNA expression reduced replication of HIV-1 in TZM-bl cells and CD4+ T cells successfully. HIV-1 susceptible TZM-bl cells were transducted with the dlhRNA expressing lentiviral vector and sorted by fluorescence-activated cell sorting to obtain stable dlhRNA expressing cells. The generation of four anti-HIV siRNAs in these dlhRNA expressing cells was verified by stem-loop RT-PCR assay. dlhRNA expression did not activate a non-specific interferon response. The dlhRNA expressing cells were also challenged with HIV-1 NL4-3, which revealed that stable expression of combinatorial siRNAs repressed HIV-1 replication for 8 days, after which HIV-1 overcame the inhibitory effect of siRNA expression by expressing mutant versions of RNAi targets. The results of this evaluation of the long-term inhibitory effects of combinatorial siRNAs against HIV-1 provide a reference for researchers who utilize combinatorial RNA interference against HIV-1 or other error-prone viruses.

DC-SIGN plays a stronger role than DCIR in mediating HIV-1 capture and transfer

The C-type lectin receptors (CLRs) expressed on dendritic cells (DCs), in particular DC-SIGN and DCIR, likely play an important role in HIV-1 early infection. Here, we systematically compared the capture and transfer capability of DC-SIGN and DCIR using a wide range of HIV-1 isolates. Our results indicated that DC-SIGN plays a stronger role than DCIR in DC-mediated HIV-1 capture and transfer. This was further strengthened by the data from transient and stable transfectants, showing that DC-SIGN had better capability, compared with DCIR in HIV-1 capture and transfer. Following constructing and analyzing a series of soluble DC-SIGN and DCIR truncates and chimeras, we demonstrated that the neck domain, but not the CRD, renders DC-SIGN higher binding affinity to gp120 likely via the formation of tetramerization. Our findings provide insights into CLR-mediated HIV-1 capture and transfer, highlighting potential targets for intervention strategies against gp120-CLR interactions.

All-trans retinoic acid prevents epidural fibrosis through NF-κB signaling pathway in post-laminectomy rats

Laminectomy is a widely accepted treatment for lumbar disorders, and epidural fibrosis (EF) is a common complication. EF is thought to cause post-operative pain recurrence after laminectomy or discectomy. All-trans retinoic acid (ATRA) has shown anti-fibrotic, anti-inflammatory, and anti-proliferative functions. The object of this study was to investigate the effects of ATRA on the prevention of EF in post-laminectomy rats. In vitro, the anti-fibrotic effect of ATRA was demonstrated with cultured fibroblasts count, which comprised of those that were cultured with/without ATRA. In vivo, rats underwent laminectomy at the L1-L2 levels. We first demonstrated the beneficial effects using 0.05% ATRA compared to vehicle (control group). We found that a higher concentration of ATRA (0.1%) achieved dose-dependent results. Hydroxyproline content, Rydell score, vimentin-positive cell density, fibroblast density, inflammatory cell density and inflammatory factor expression levels all suggested better outcomes in the 0.1% ATRA rats compared to the other three groups. Presumably, these effects involved ATRA's ability to suppress transforming growth factor (TGF-β1) and interleukin (IL)-6 which was confirmed with reverse-transcriptase polymerase chain reaction (RT-PCR). Finally we demonstrated that ATRA down-regulated nuclear factor (NF)-κB by immunohistochemistry and western blotting for p65 and inhibition of κB (IκBα), respectively. Our findings indicate that topical application of ATRA can inhibit fibroblast proliferation, decrease TGF-β1 and IL-6 expression level, and prevent epidural scar adhesion in rats. The highest concentration employed in this study (0.1%) was the most effective. ATRA suppressed EF through down-regulating NF-κB signaling, whose specific mechanism is suppression of IκB phosphorylation and proteolytic degradation.