During chronic viral infection, virus-specific CD8(+) T cells become exhausted, exhibit poor effector function and lose memory potential. However, exhausted CD8(+) T cells can still contain viral replication in chronic infections, although the mechanism of this containment is largely unknown. Here we show that a subset of exhausted CD8(+) T cells expressing the chemokine receptor CXCR5 has a critical role in the control of viral replication in mice that were chronically infected with lymphocytic choriomeningitis virus (LCMV). These CXCR5(+) CD8(+) T cells were able to migrate into B-cell follicles, expressed lower levels of inhibitory receptors and exhibited more potent cytotoxicity than the CXCR5(-) [corrected] subset. Furthermore, we identified the Id2-E2A signalling axis as an important regulator of the generation of this subset. In patients with HIV, we also identified a virus-specific CXCR5(+) CD8(+) T-cell subset, and its number was inversely correlated with viral load. The CXCR5(+) subset showed greater therapeutic potential than the CXCR5(-) [corrected] subset when adoptively transferred to chronically infected mice, and exhibited synergistic reduction of viral load when combined with anti-PD-L1 treatment. This study defines a unique subset of exhausted CD8(+) T cells that has a pivotal role in the control of viral replication during chronic viral infection.

We recently derived mouse expanded potential stem cells (EPSCs) from individual blastomeres by inhibiting the critical molecular pathways that predispose their differentiation 1. EPSCs had enriched molecular signatures of blastomeres and possessed the developmental potency for all embryonic and extraembryonic cell lineages. Here, we report the derivation of porcine EPSCs, which express key pluripotency genes, are genetically stable, permit genome editing, differentiate to derivatives of the three germ layers in chimeras, and produce primordial germ celllike cells in vitro. Under similar conditions, human ESCs and iPSCs can be converted, or somatic cells directly reprogrammed, to EPSCs that display the molecular and functional attributes reminiscent of porcine EPSCs. Significantly, trophoblast stem cell-like cells can be generated from both human and porcine EPSCs. Our pathwayinhibition paradigm thus opens a new avenue for generating mammalian pluripotent stem cells, and EPSCs present an unique cellular platform for translational research in biotechnology and regenerative medicine.

Highlights d RNA-seq of oocytes and granulosa cells mapped transcriptome and signature genes d KEGG/GSEA analysis uncovered pathways involved in primordial follicle activation d Oocyte-granulosa cell interactions exhibit stage-and species-specific patterns d RNA-seq analysis identified candidate secretory biomarkers of ovarian reserve

Highlights d Single-cell transcriptomic roadmap of NHP ovarian aging d Molecular signatures revealed for NHP oocytes at stepwise developmental stages d Cell-type-specific inactivation of antioxidant genes in aged monkey and human ovaries

Highlights d A method that enables the generation of blastocyst-like structures from EPS cells d EPS-blastoids resemble blastocysts in morphology and celllineage allocation d EPS-blastoid formation recapitulates early developmental events in vitro d EPS-blastoids are able to implant in utero

Zika virus (ZIKV) is associated with neonatal microcephaly and Guillain-Barré syndrome. While progress has been made in understanding the causal link between ZIKV infection and microcephaly, the life cycle and pathogenesis of ZIKV are less well understood. In particular, there are conflicting reports on the role of AXL, a TAM family kinase receptor that was initially described as the entry receptor for ZIKV. Here, we show that while genetic ablation of AXL protected primary human astrocytes and astrocytoma cell lines from ZIKV infection, AXL knockout did not block the entry of ZIKV. We found, instead, that the presence of AXL attenuated the ZIKV-induced activation of type I interferon (IFN) signalling genes, including several type I IFNs and IFN-stimulating genes. Knocking out type I IFN receptor α chain (IFNAR1) restored the vulnerability of AXL knockout astrocytes to ZIKV infection. Further experiments suggested that AXL regulates the expression of SOCS1, a known type I IFN signalling suppressor, in a STAT1/STAT2-dependent manner. Collectively, our results demonstrate that AXL is unlikely to function as an entry receptor for ZIKV and may instead promote ZIKV infection in human astrocytes by antagonizing type I IFN signalling.

Cancer-secreted exosomal miRNAs are emerging mediators of cancer-stromal cross-talk in the tumor environment. Our previous miRNAs array of cervical squamous cell carcinoma (CSCC) clinical specimens identified upregulation of miR-221-3p. Here, we show that miR-221-3p is closely correlated with peritumoral lymphangiogenesis and lymph node (LN) metastasis in CSCC. More importantly, miR-221-3p is characteristically enriched in and transferred by CSCC-secreted exosomes into human lymphatic endothelial cells (HLECs) to promote HLECs migration and tube formation in vitro, and facilitate lymphangiogenesis and LN metastasis in vivo according to both gain-of-function and loss-of-function experiments. Furthermore, we identify vasohibin-1 (VASH1) as a novel direct target of miR-221-3p through bioinformatic target prediction and luciferase reporter assay. Re-expression and knockdown of VASH1 could respectively rescue and simulate the effects induced by exosomal miR-221-3p. Importantly, the miR-221-3p-VASH1 axis activates the ERK/AKT pathway in HLECs independent of VEGF-C. Finally, circulating exosomal miR-221-3p levels also have biological function in promoting HLECs sprouting in vitro and are closely associated with tumor miR-221-3p expression, lymphatic VASH1 expression, lymphangiogenesis, and LN metastasis in CSCC patients. In conclusion, CSCC-secreted exosomal miR-221-3p transfers into HLECs to promote lymphangiogenesis and lymphatic metastasis via downregulation of VASH1 and may represent a novel diagnostic biomarker and therapeutic target for metastatic CSCC patients in early stages.

Maternal obese environment has been reported to induce oxidative stress and meiotic defects in oocytes, however the underlying molecular mechanism remains unclear. Here, using mice fed a high fat diet (HFD) as an obesity model, we first detected enhanced reactive oxygen species (ROS) content and reduced Sirt3 expression in HFD oocytes. We further observed that specific depletion of Sirt3 in control oocytes elevates ROS levels while Sirt3 overexpression attenuates ROS production in HFD oocytes, with significant suppression of spindle disorganization and chromosome misalignment phenotypes that have been reported in the obesity model. Candidate screening revealed that the acetylation status of lysine 68 on superoxide dismutase (SOD2K68) is dependent on Sirt3 deacetylase activity in oocytes, and acetylation-mimetic mutant SOD2K68Q results in almost threefold increase in intracellular ROS. Moreover, we found that acetylation levels of SOD2K68 are increased by ~80% in HFD oocytes and importantly, that the non-acetylatable-mimetic mutant SOD2K68R is capable of partially rescuing their deficient phenotypes. Together, our data identify Sirt3 as an important player in modulating ROS homeostasis during oocyte development, and indicate that Sirt3-dependent deacetylation of SOD2 plays a protective role against oxidative stress and meiotic defects in oocytes under maternal obese conditions.