Foamy viruses are members of the Retroviridae family\'s Spumaretrovirinae subfamily. They induce cell vacuolation and exhibit a foamy pathogenic impact after infecting cells. DACH1 (dachshund family transcription factor 1) is a crucial cytokine linked to tumor development, and is associated with the growth of many different malignant tumor cells. Additionally, DACH1 suppresses pancreatic cell proliferation and is involved in diabetes insulin signaling. Prototype foamy viruses (PFVs) were used for the investigation of the regulatory mechanism of FVs on cellular DACH1 expression. The results show that DACH1 expression in PFV-infected cells was inconsistent at both the transcriptional and protein levels. At the transcriptional level, DACH1 was significantly activated by PFV transactivator Tas, and dual-luciferase reporter gene tests, EMSA, and ChIP assays found a Tas response element of 21 nucleotides in the DACH1 promoter. PFV and Tas did not boost the levels of DACH1 protein in a manner consistent with the high levels of DACH1 transcription expression. It was noted that Tas increased the expression of the Ser/Thr protein phosphatase PPM1E, causing PPM1E-mediated post-translational SUMOylation alterations of DACH1 to prompt DACH1 to degrade. The reason for DACH1 protein degradation is that DACH1 inhibits PFV replication. To sum up, these findings show that PFV upregulated the transcription of DACH1, while urging its protein into PPM1E-mediated SUMOylation, to eliminate the adverse effect of DACH1 overexpression of host cells on viral replication and promote virus survival.

OBJECTIVE: To describe a new surgical technique and outcomes of lens-sparing vitrectomy and retrolental stalk dissection in posterior persistent fetal vasculature (PFV).
METHODS: Retrospective interventional case series.
METHODS: RESULTS: Among the 21 included eyes, 8 (38%) had no macular involvement and 4 (19%) presented with microphthalmia. Median age at the first surgery was 8 months (range: 1-113 months). Surgical success was obtained in 71.4% of cases (15 of 21). In the remaining cases, the lens was removed because of capsular rupture in 2 cases (9.5%) and a large capsular opacity after stalk removal or an adherent stalk impossible to dissect in 4 cases (19.1%). In the capsular bag, IOL implantation was accomplished for all but 1 eye. None of the eyes developed retinal detachment or required glaucoma surgery. Endophthalmitis occurred in 1 eye. Secondary lens aspiration was needed in 3 eyes after a mean interval of 10.7 months following initial surgery. At last follow-up, half of the eyes remained phakic.
CONCLUSIONS: Lens-sparing vitrectomy is a useful approach to addressing the retrolental stalk in selected cases of persistent fetal vasculature syndrome. By delaying or avoiding lens extraction, this approach allows preservation of accommodation, reduction of the risk of aphakia, glaucoma, and development of secondary lens reproliferation.

OBJECTIVE: This study aims to investigate surgical outcomes of eyes with severe anterior persistent fetal vasculature (PFV) and the role of associated anatomical anomalies on prognosis.
METHODS: This is a retrospective, comparative case series of 32 eyes of 31 patients who underwent vitreoretinal surgery for severe anterior PFV, defined as fibrovascular tissue totally covering the back of cataractous lens. Based on the degree of anterior retinal elongations, cases were classified as follows: group 1, eyes with well-developed pars plana and minor/no abnormalities (n = 11, 34%); group 2, eyes with partially developed pars plana and broad-based elongations (n = 9, 28%); and group 3, eyes with no visible pars plana and fibrovascular membrane having 360° continuity with peripheral retina (n = 12, 38%). Complications and functional and anatomical outcomes were investigated.
RESULTS: The median surgical age was 2 (1-12) months. The median follow-up was 26 (6-120) months. Seventy-three percent in group 1 achieved finger counting or better vision with a single surgery and without any pupillary/retinal complication. Groups 2 and 3 required 2.1 ± 0.9 and 2.6 ± 1.2 surgeries on average. Pupillary obliteration and RD occurred in 33% and 22% in group 2 and 58% and 67% in group 3. Retina remained attached after silicone oil removal in 89% of group 2 and 25% of group 3. Phthisis developed in 50% in group 3.
CONCLUSIONS: Peripheral retinal anomalies are common in severe anterior PFV and have a major impact on prognosis. Prognosis is favorable in cases with mild-to-moderate anomalies with appropriate management of possible retinal tears. In eyes with 360° retinal elongations, severe fibrous proliferation and eventual eye loss are common.

In most cases, proteolytic processing of the retroviral Pol portion of the Gag-Pol polyprotein precursor produces protease (PR), reverse transcriptase (RT), and integrase (IN). However, foamy viruses (FVs) express Pol separately from Gag and, when Pol is processed, only the IN domain is released. Here, we report a 2.9 Å resolution crystal structure of the mature PR-RT from prototype FV (PFV) that can carry out both proteolytic processing and reverse transcription but is in a configuration not competent for proteolytic or polymerase activity. PFV PR-RT is monomeric and the architecture of PFV PR is similar to one of the subunits of HIV-1 PR, which is a dimer. There is a C-terminal extension of PFV PR (101-145) that consists of two helices which are adjacent to the base of the RT palm subdomain, and anchors PR to RT. The polymerase domain of PFV RT consists of fingers, palm, thumb, and connection subdomains whose spatial arrangements are similar to the p51 subunit of HIV-1 RT. The RNase H and polymerase domains of PFV RT are connected by flexible linkers. Significant spatial and conformational (sub)domain rearrangements are therefore required for nucleic acid binding. The structure of PFV PR-RT provides insights into the conformational maturation of retroviral Pol polyproteins.

Persistent fetal vasculature (PFV), previously known as persistent hyperplastic primary vitreous, is a developmental malformation of the eyes that is caused by a failure of the hyaloid vasculature to regress in utero. PFV has been reported for decades; however, our understanding of the pathophysiology/pathogenesis of PFV, and the diagnostic and treatment modalities for PFV have evolved over time, and these advancements have improved diagnosis, treatment, and outcomes. However and in spite of these advancements, the heterogeneity of this disease continues to make PFV a diagnostic challenge. Here, we review what is currently known about various important aspects of PFV to update and enhance the knowledge of ophthalmologists who encounter and manage PFV in clinical practice.

The family of human APOBEC3 (A3) restriction factors is formed by seven different proteins, A3A-D and A3F-H. Among these A3s, A3B harbors strong restriction activity against several retroviruses, such as SIV, and MLV. How lentiviruses and other retroviruses, prevalent in many primate species, counteract A3B is poorly understood. In this study, we found that A3B strongly inhibited SIVmac and HIV-2 infectivity, which was antagonized by their Vif proteins. Both SIVmac and HIV-2 Vifs diminished the protein level of A3B in viral producer cells, and hindered A3B incorporation into viral particles. We observed that HIV-2 Vif binds A3B and induces its degradation by assembly of an A3-Vif-CUL5-ElonginB/C E3-ligase complex. A3B and HIV-2 Vif localize and interact in the nucleus. In addition, we also found that the accessory protein Bet of prototype foamy virus (PFV) significantly antagonized the anti-SIVmac activity of A3B. Like Vif, Bet prevented the incorporation of A3B into viral particles. However, in contrast to Vif Bet did not induce the degradation of A3B. Rather, Bet binds A3B to block formation of high molecular weight A3B complexes and induces A3B cytoplasmic trapping. In summary, these findings indicate that A3B is recognized by diverse retroviruses and counteracted by virus-specific pathways that could be targeted to inhibit A3B mutating activity in cancers.

Non-small cell lung cancer (NSCLC) is a malignant cancer characterized by easy invasion, metastasis and poor prognosis, so that conventional chemotherapy cannot inhibit its invasion and metastasis. Doxorubicin (DOX), as a broad-spectrum antitumour drug, cannot be widely used in clinic because of its poor targeting, short half-life, strong toxicity and side effects. Therefore, the aim of our study is to construct a kind of PFV modified DOX plus schisandrin B liposomes to solve the above problems, and to explore its potential mechanism of inhibiting NSCLC invasion and metastasis. The antitumour efficiency of the targeting liposomes was carried out by cytotoxicity, heating ablation, wound healing, transwell, vasculogenic mimicry channels formation and metastasis-related protein tests in vitro. Pharmacodynamics were evaluated by tumour inhibition rate, HE staining and TUNEL test in vivo. The enhanced anti-metastatic mechanism of the targeting liposomes was attributed to the downregulation of vimentin, vascular endothelial growth factor, matrix metalloproteinase 9 and upregulation of E-cadherin. In conclusion, the PFV modified DOX plus schisandrin B liposomes prepared in this study provided a treatment strategy with high efficiency for NSCLC.

As a malignant tumor, breast cancer is very prone to metastasis. Chemotherapy is one of the most common means for treating breast cancer. However, due to the serious metastasis and the poor targeting effect of traditional chemotherapeutic drugs, even after years of efforts, the therapeutic effect is still unsatisfied. Therefore, in this study, we constructed a kind of PFV modified epirubicin plus schisandrin B liposomes to solve the above disadvantages. In vitro experiments showed that the targeting liposomes with ideal physicochemical property could increase the cytotoxicity of MDA-MB-435S cells, destroy the formation of vasculogenic mimicry (VM), and inhibit tumor invasion and migration. Action mechanisms indicated that the inhibition of targeting liposomes on tumor metastasis was attributed to the regulation of the expression of vascular endothelial growth factor (VEGF), matrix metalloproteinase-9 (MMP-9), vimentin (VIM), and E-cadherin (E-cad). In vivo pharmacodynamic experiments showed that the targeting liposomes could significantly improve the antitumor effect in mice. H&E staining and TUNEL results showed that the targeting liposomes could promote the apoptosis of tumor cells. Hence, the PFV modified epirubicin plus schisandrin B liposomes constructed in this study provided a new therapeutic strategy for breast cancer.

A 10 year old girl present with both eyes central cataract with posterior lenticonus. Intraoperative, she was noted to have both eyes persistent fetal vasculature (PFV). To the best of our knowledge, association of bilateral posterior lenticonus and PFV has not been reported before. This supports the hypothesis that PFV has a role in pathogenesis of posterior lenticonus.

Human BST2 (hBST2, also called Tetherin) is a host restriction factor that blocks the release of various enveloped viruses. BST2s from different mammals also possess antiviral activity. Bovine BST2s (bBST2s), bBST2A1 and bBST2A2, reduce production of cell-free bovine leukemia virus (BLV) and vesicular stomatitis virus (VSV). However, the effect of bBST2 on other retroviruses remains unstudied.
Here, we studied the antiviral activity of wildtype and mutant bBST2A1 proteins on retroviruses including human immunodeficiency virus type 1 (HIV-1), prototypic foamy virus (PFV), bovine foamy virus (BFV) and bovine immunodeficiency virus (BIV). The results showed that wildtype bBST2A1 suppressed the release of HIV-1, PFV and BFV. We also generated bBST2A1 mutants, and found that GPI anchor and dimerization, but not glycosylation, are essential for antiviral activity of bBST2A1. Moreover, unlike hBST2, bBST2A1 displayed no inhibitory effect on cell-to-cell transmission of PFV, BFV and BIV.
Our data suggested that bBST2A1 inhibited retrovirus release, however, had no effect on cell-to-cell transmission of retroviruses.