Keap1 recognizes EIAV early accessory protein Rev to promote antiviral defense.

The Nrf2/Keap1 axis plays a complex role in viral susceptibility, virus-associated inflammation and immune regulation in host cells. However, whether or how the Nrf2/Keap1 axis is involved in the interactions between equine lentiviruses and their hosts remains unclear. Here, we demonstrate that the Nrf2/Keap1 axis was activated during EIAV infection. Mechanistically, EIAV-Rev competitively binds to Keap1 and releases Nrf2 from Keap1-mediated repression, leading to the accumulation of Nrf2 in the nucleus and promoting Nrf2 responsive genes transcription. Subsequently, we demonstrated that the Nrf2/Keap1 axis represses EIAV replication via two independent molecular mechanisms: directly increasing antioxidant enzymes to promote effective cellular resistance against EIAV infection, and repression of Rev-mediated RNA transport through direct interaction between Keap1 and Rev. Together, these data suggest that activation of the Nrf2/Keap1 axis mediates a passive defensive response to combat EIAV infection. The Nrf2/Keap1 axis could be a potential target for developing strategies for combating EIAV infection.

SARS-CoV-2 hijacks macropinocytosis to facilitate its entry and promote viral spike-mediated cell-to-cell fusion.

Revealing the mechanisms of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) entry and cell-to-cell spread might provide insights for understanding the underlying mechanisms of viral pathogenesis, tropism, and virulence. The signaling pathways involved in SARS-CoV-2 entry and viral spike-mediated cell-to-cell fusion remain elusive. In the current study, we found that macropinocytosis inhibitors significantly suppressed SARS-CoV-2 infection at both the entry and viral spike-mediated cell-to-cell fusion steps. We demonstrated that SARS-CoV-2 entry required the small GTPase Rac1 and its effector kinase p21-activated kinase 1 by dominant-negative and RNAi assays in human embryonic kidney 293T-angiotensin-converting enzyme 2 cells and that the serine protease transmembrane serine protease 2 reversed the decrease in SARS-CoV-2 entry caused by the macropinocytosis inhibitors. Moreover, in the cell-to-cell fusion assay, we confirmed that macropinocytosis inhibitors significantly decreased viral spike-mediated cell-to-cell fusion. Overall, we provided evidence that SARS-CoV-2 utilizes a macropinocytosis pathway to enter target cells and to efficiently promote viral spike-mediated cell-to-cell fusion.

Genome-wide analysis of long noncoding RNA profiles in pseudorabies-virus-infected PK15 cells.

Recently, an increasing number of studies have shown that long noncoding RNAs (lncRNAs) are involved in host metabolism after infection with pseudorabies virus (PRV). In our study, via RNA sequencing analysis, a total of 418 mRNAs, 137 annotated lncRNAs, and 312 new lncRNAs were found to be differentially expressed. These lncRNAs were closely associated with metabolic regulation and immunity-related signalling pathways, including the T-cell receptor signalling pathway, chemokine signalling pathway, mitogen-activated protein kinase (MAPK) signalling pathway, TNF signalling pathway, Ras signalling pathway, calcium signalling pathway, and phosphatidylinositol signalling system. Real-time PCR indicated that several mRNAs and lncRNAs involved in the regulation of the immune effector process, T-cell receptor signalling pathway, TNF signalling pathway, MAPK signalling pathway, and chemokine signalling pathways were significantly expressed. These mRNAs and lncRNAs might play a role in PRV infection.

FZD5 prevents epithelial-mesenchymal transition in gastric cancer.

BACKGROUND: Frizzled (FZD) proteins function as receptors for WNT ligands. Members in FZD family including FZD2, FZD4, FZD7, FZD8 and FZD10 have been demonstrated to mediate cancer cell epithelial-mesenchymal transition (EMT). METHODS: CCLE and TCGA databases were interrogated to reveal the association of FZD5 with EMT. EMT was analyzed by investigating the alterations in CDH1 (E-cadherin), VIM (Vimentin) and ZEB1 expression, cell migration and cell morphology. Transcriptional modulation was determined by ChIP in combination with Real-time PCR. Survival was analyzed by Kaplan-Meier method. RESULTS: In contrast to other FZDs, FZD5 was identified to prevent EMT in gastric cancer. FZD5 maintains epithelial-like phenotype and is negatively modulated by transcription factors SNAI2 and TEAD1. Epithelial-specific factor ELF3 is a downstream effecter, and protein kinase C (PKC) links FZD5 to ELF3. ELF3 represses ZEB1 expression, further guarding against EMT. Moreover, FZD5 signaling requires its co-receptor LRP5 and WNT7B is a putative ligand for FZD5. FZD5 and ELF3 are associated with longer survival, whereas SNAI2 and TEAD1 are associated with shorter survival. CONCLUSIONS: Taken together, FZD5-ELF3 signaling blocks EMT, and plays a potential tumor-suppressing role in gastric cancer. Video Abstract.

Higher circular RNA_0015278 correlates with absence of extrathyroidal invasion, lower pathological tumor stages, and prolonged disease-free survival in papillary thyroid carcinoma patients.

BACKGROUND: Circular RNA_0015278 (circ_0015278) inhibits the progression of several cancers and is greatly reduced in papillary thyroid carcinoma (PTC) tissues compared with benign thyroid lesions by microarray profiling. This study aimed to further investigate the correlation of circ_0015278 with tumor characteristics and prognosis in PTC patients. METHODS: Totally, 206 PTC patients who underwent tumor resection were retrospectively enrolled; subsequently, circ_0015278 expression in their tumor and adjacent tissues was detected by reverse transcriptional-quantitative polymerase chain reaction. Besides, disease-free survival (DFS) and overall survival (OS) were calculated. RESULTS: Circ_0015278 was reduced in tumor tissues compared with adjacent tissues (p < 0.001), and receiver operating characteristic analysis showed that it well discriminated tumor tissues from adjacent tissues (area under curve: 0.903, 95% confidence interval: 0.874-0.932). Besides, higher tumor circ_0015278 expression was correlated with absence of extrathyroidal invasion (p = 0.036), lower pathological tumor (pT) stage (p = 0.05), pathological node (pN) stage (p = 0.002), and pathological tumor-node-metastasis (pTNM) stage (p = 0.001). Moreover, higher tumor circ_0015278 expression was associated with a reduced relapse rate (p = 0.011), but not mortality rate (p = 0.110); meanwhile, it was also correlated with prolonged DFS (p = 0.017), but not OS (p = 0.136). Additionally, multivariate Cox's regression analyses showed that higher tumor circ_0015278 expression independently associated with favorable DFS (p = 0.026, hazard ratio = 0.529). CONCLUSION: Circ_0015278 is reduced in tumor tissues, while its' higher expression in tumor correlates with absence of extrathyroidal invasion, lower pT, pN, and pTNM stage, as well as prolonged DFS in PTC patients.

ANP32A and ANP32B are key factors in the Rev-dependent CRM1 pathway for nuclear export of HIV-1 unspliced mRNA.

The nuclear export receptor CRM1 is an important regulator involved in the shuttling of various cellular and viral RNAs between the nucleus and the cytoplasm. HIV-1 Rev interacts with CRM1 in the late phase of HIV-1 replication to promote nuclear export of unspliced and single spliced HIV-1 transcripts. However, other cellular factors involved in the CRM1-dependent viral RNA nuclear export remain largely unknown. Here, we demonstrate that ANP32A and ANP32B mediate the export of unspliced or partially spliced viral mRNA via interactions with Rev and CRM1. We found that a double, but not single, knockout of ANP32A and ANP32B significantly decreased the expression of gag protein. Reconstitution of either ANP32A or ANP32B restored the viral production equally. Disruption of both ANP32A and ANP32B expression led to a dramatic accumulation of unspliced viral mRNA in the nucleus. We further identified that ANP32A and ANP32B interact with both Rev and CRM1 to promote RNA transport. Our data strongly suggest that ANP32A and ANP32B play an important role in the Rev-CRM1 pathway, which is essential for HIV-1 replication, and our findings provide a candidate therapeutic target for host defense against retroviral infection.

Attenuation of Equine Lentivirus Alters Mitochondrial Protein Expression Profile from Inflammation to Apoptosis.

Equine infectious anemia virus (EIAV) is an equine lentivirus similar to HIV-1, targets host immune cells, and causes a life-long infection in horses. The Chinese live EIAV vaccine is attenuated from long-term passaging of a highly virulent strain in vitro The parent pathogenic strain (EIAVDLV34) induces a host inflammatory storm to cause severe pathological injury of animals. However, the vaccine strain (EIAVDLV121) induces a high level of apoptosis to eliminate infected cells. To investigate how these processes are regulated, we performed a comparative proteomics analysis and functional study in equine monocyte-derived macrophages (eMDMs) and found that the divergent mitochondrial protein expression profiles caused by EIAV strains with different virulence led to disparate mitochondrial function, morphology, and metabolism. This in turn promoted the distinct transformation of macrophage inflammatory polarization and intrinsic apoptosis. In EIAVDLV34-infected cells, a high level of glycolysis and increased mitochondrial fragmentation were induced, resulting in the M1-polarized proinflammatory-type transformation of macrophages and the subsequent production of a strong inflammatory response. Following infection with EIAVDLV121, the infected cells were transformed into M2-polarized anti-inflammatory macrophages by inhibition of glycolysis. In this case, a decrease in the mitochondrial membrane potential and impairment of the electron transport chain led to increased levels of apoptosis and reactive oxygen species. These results correlated with viral pathogenicity loss and may help provide an understanding of the key mechanism of lentiviral attenuation.IMPORTANCE Following viral infection, the working pattern and function of the cell can be transformed through the impact on mitochondria. It still unknown how the mitochondrial response changes in cells infected with viruses in the process of virulence attenuation. EIAVDLV121 is the only effective lentiviral vaccine for large-scale use in the world. EIAVDLV34 is the parent pathogenic strain. Unlike EIAVDLV34-induced inflammation storms, EIAVDLV121 can induce high levels of apoptosis. For the first time, we found that, after the mitochondrial protein expression profile is altered, EIAVDLV34-infected cells are transformed into M1-polarized-type macrophages and cause inflammatory injury and that the intrinsic apoptosis pathway is activated in EIAVDLV121-infected cells. These studies shed light on how the mitochondrial protein expression profile changes between cells infected by pathogenic lentivirus strains and cells infected by attenuated lentivirus strains to drive different cellular responses, especially from inflammation to apoptosis.

Non-canonical Fzd7 signaling contributes to breast cancer mesenchymal-like stemness involving Col6a1.

Mesenchymal-like stemness is characterized by epithelial-mesenchymal transition (EMT). Breast cancer (BC) cell mesenchymal-like stemness is responsible for distal lung metastasis. Interrogation of databases showed that Fzd7 was closely associated with a panel of mesenchymal-related genes and a panel of stemness-related genes. Fzd7 knockdown in mesenchymal-like MDA-MB-231 and Hs578T cells reduced expression of Vimentin, Slug and Zeb1, induced an epithelial-like morphology, inhibited cell motility, impaired mammosphere formation and decreased Lgr5+ subpopulation. In contrast, Fzd7 overexpression in MCF7 cells resulted in opposite changes. Fzd7 knockdown delayed xenograft tumor formation, suppressed tumor growth, and impaired lung metastasis. Mechanistically, Fzd7 combined with Wnt5a/b and modulated expression of phosphorylated Stat3 (p-STAT3), Smad3 and Yes-associated protein 1 (Yap1). Moreover, Fzd7-Wnt5b modulated expression of collagen, type VI, alpha 1 (Col6a1). Both Wnt5b knockdown and Col6a1 knockdown disrupted BC cell mesenchymal phenotype and stemness. Taken together, Fzd7 contributes to BC cell EMT and stemness, inducing tumorigenesis and metastasis, mainly through a non-canonical Wnt5b pathway. Col6a1 is implicated in Fzd7-Wnt5b signaling, and mediates Fzd7-Wnt5b -induced mesenchymal-like stemness. Video Abstract.

LGR4 maintains HGSOC cell epithelial phenotype and stem-like traits.

OBJECTIVE: High-grade serous ovarian cancer (HGSOC) is lethal mainly due to extensive metastasis. Cancer cell stem-like properties are responsible for HGSOC metastasis. LGR4, a G-protein-coupled receptor, is involved in the maintenance of stem cell self-renewal and activity in some human organs. METHODS: TCGA and CCLE databases were interrogated for gene mRNA in ovarian cancer tissues and cell lines. Gain and loss of functions of LGR4, ELF3, FZD5 and WNT7B were performed to identify their roles in ovarian cancer cell epithelial phenotype and stem-like properties. In vivo experiments were performed to observe the effect of LGR4 on ovarian cancer cell growth and peritoneal seeding. The binding of ELF3 to LGR4 gene promoter was investigated by dual-luciferase reporter assays and ChIP. RESULTS: LGR4 was shown to be overexpressed in HGSOCs and maintain the epithelial phenotype of HGSOC cells. LGR4 knockdown suppressed POU5F1, SOX2, PROM1 (CD133) and ALDH1A2 expression. Furthermore, LGR4 knockdown reduced CD133+ and ALDH+ subpopulations and impaired tumorisphere formation. To the contrary, LGR4 overexpression enhanced POU5F1 and SOX2 expression and tumorisphere formation capacity. LGR4 knockdown inhibited HGSOC cell growth and peritoneal seeding in xenograft models. Mechanistically, LGR4 and ELF3, an epithelium-specific transcription factor, formed a reciprocal regulatory loop, which was positively modulated by WNT7B/FZD5 ligand-receptor pair. Consistently, knockdown of ELF3, WNT7B, and FZD5, respectively, disrupted HGSOC cell epithelial phenotype and stem-like properties. CONCLUSION: Together, these data demonstrate that WNT7B/FZD5-LGR4/ELF3 axis maintains HGSOC cell epithelial phenotype and stem-like traits; targeting this axis may prevent HGSOC metastasis.

Lnc-MEG3 acts as a potential biomarker for predicting increased disease risk, systemic inflammation, disease severity, and poor prognosis of sepsis via interacting with miR-21.

BACKGROUND: This study aimed to investigate the correlations of long non-coding RNA maternally expressed gene 3 (lnc-MEG3), microRNA (miR)-21, and lnc-MEG3/miR-21 axis with disease risk, inflammation, disease severity, and 28-day mortality of sepsis. METHODS: Totally, 219 sepsis patients and 219 health controls (HCs) were enrolled. Plasma samples were obtained from sepsis patients within 24 hours after admission and from HCs on enrollment to detect lnc-MEG3 and miR-21 expressions by real-time quantitative polymerase chain reaction. RESULTS: The lnc-MEG3 expression and lnc-MEG3/miR-21 axis were increased, while miR-21 expression was decreased in sepsis patients compared with HCs. Lnc-MEG3 (area under the curve (AUC): 0.887, 95% confidence interval (CI): 0.856-0.917) and lnc-MEG3/miR-21 axis (AUC: 0.934, 95% CI: 0.909-0.958) had good values for predicting elevated sepsis risk, while miR-21 (AUC: 0.801, 95% CI: 0.758-0.844) presented a good predictive value for reduced sepsis risk. Furthermore, lnc-MEG3 expression and lnc-MEG3/miR-21 axis positively correlated with, whereas miR-21 expression negatively correlated with acute pathologic and chronic health evaluation II, sequential organ failure assessment score, serum creatinine, C-reactive protein, tumor necrosis factor-α, interleukin (IL)-1ß, IL-6, and IL-17 in sepsis patients. Additionally, lnc-MEG3 (AUC: 0.704, 95% CI: 0.626-0.783) and lnc-MEG3/miR-21 axis (AUC: 0.669, 95% CI: 0.589-0.750) exhibited acceptable values in predicting higher 28-day mortality risk, while miR-21 (AUC: 0.588, 95% CI: 0.505-0.672) presented a poor predictive value for lower 28-day mortality risk in sepsis patients. CONCLUSION: Lnc-MEG3 might serve as a potential biomarker for the development, progression, and prognosis prediction of sepsis via interacting with miR-21.

The predictive value of microRNA-21 for sepsis risk and its correlation with disease severity, systemic inflammation, and 28-day mortality in sepsis patients.

BACKGROUND: This study aimed to investigate the value of microRNA (miR)-21 for predicting sepsis risk and its correlation with inflammation, disease severity as well as 28-day mortality in sepsis patients. METHODS: Totally, 219 sepsis patients and 219 healthy controls (HCs) were recruited. Plasma samples were obtained from sepsis patients within 24 hours after admission and from HCs at the enrollment to detect miR-21 expressions by real-time quantitative polymerase chain reaction. Besides, the clinical characteristics of sepsis patients were recorded and the 28-day mortality of sepsis patients was evaluated. RESULTS: MiR-21 expression was decreased in sepsis patients compared with HCs, and further receiver operating characteristic (ROC) curve analysis revealed that miR-21 was of a good value in predicting sepsis risk (area under the curve [AUC]: 0.801, 95% CI: 0.758-0.844). Besides, miR-21 expression was negatively associated with acute pathologic and chronic health evaluation II (APACHE II) and sequential organ failure assessment (SOFA) score in sepsis patients. Furthermore, miR-21 expression was negatively correlated with serum creatinine, C-reactive protein, tumor necrosis factor-α, interleukin (IL)-1ß, IL-6, and IL-17, while positively correlated with albumin in sepsis patients. However, there was no correlation of miR-21 expression with white blood cell, smoke, or comorbidities in sepsis patients. Additionally, ROC curve analysis displayed that miR-21 exhibited a poor predictive value for 28-day mortality risk in sepsis patients (AUC: 0.588, 95% CI: 0.505-0.672). CONCLUSION: MiR-21 might serve as a potential biomarker for the development and progression of sepsis, while not for prognosis prediction in sepsis patients.

Rhesus monkey TRIM5α protein SPRY domain contributes to AP-1 activation.

TRIM5α is an important host restriction factor that could potently block retrovirus infection. The SPRY domain of TRIM5α mediates post-entry restriction by recognition of and binding to the retroviral capsid. Human TRIM5α also functions as an innate immune sensor to activate AP-1 and NF-κB signaling, which subsequently restrict virus replication. Previous studies have shown that the AP-1 and NF-κB signaling activation relies on the RING motif of TRIM5α. In this study, we have demonstrated that the SPRY domain is essential for rhesus macaque TRIM5α to activate AP-1 but not NF-κB signaling. The AP-1 activation mainly depends on all of the ß-sheet barrel on SPRY structure of TRIM5α. Furthermore, the SPRY-mediated auto-ubiquitination of TRIM5α is required for AP-1 activation. This study reports that rhesus macaque TRIM5α mainly undergoes Lys27-linked and Met1-linked auto-polyubiquitination. Finally, we found that the TRIM5α signaling function was positively correlated with its retroviral restriction activity. This study discovered an important role of the SPRY domain in immune signaling and antiviral activity and further expanded our knowledge of the antiviral mechanism of TRIM5α.

Equine Myxovirus Resistance Protein 2 Restricts Lentiviral Replication by Blocking Nuclear Uptake of Capsid Protein.

Human myxovirus resistance protein 2 (huMxB) has been shown to be a determinant type I interferon (IFN)-induced host factor involved in the inhibition of human immunodeficiency virus type 1 (HIV-1) as well as many other primate lentiviruses. This blocking occurs after the reverse transcription of viral RNA and ahead of integration into the host DNA, which is closely connected to the ability of the protein to bind the viral capsid. To date, Mx2s derived from nonprimate animals have shown no capacity for HIV-1 suppression. In this study, we examined the restrictive effect of equine Mx2 (eqMx2) on both equine infectious anemia virus (EIAV) and HIV-1 and investigated possible mechanisms for its specific function. We demonstrated that IFN-α/ß upregulates the expression of eqMx2 in equine monocyte-derived macrophages (eMDMs). The overexpression of eqMx2 significantly suppresses the replication of EIAV, HIV-1, and simian immunodeficiency viruses (SIVs) but not that of murine leukemia virus (MLV). The knockdown of eqMx2 transcription weakens the inhibition of EIAV replication by type I interferon. Interestingly, data from immunofluorescence assays suggest that the subcellular localization of eqMx2 changes following virus infection, from being dispersed in the cytoplasm to being accumulated at the nuclear envelope. Furthermore, eqMx2 blocks the nuclear uptake of the proviral genome by binding to the viral capsid. The N-terminally truncated mutant of eqMx2 lost the ability to bind the viral capsid as well as the restriction effect for lentiviruses. These results improve our understanding of the Mx2 protein in nonprimate animals.IMPORTANCE Previous research has shown that the antiviral ability of Mx2s is confined to primates, particularly humans. EIAV has been shown to be insensitive to restriction by human MxB. Here, we describe the function of equine Mx2. This protein plays an important role in the suppression of EIAV, HIV-1, and SIVs. The antiviral activity of eqMx2 depends on its subcellular location as well as its capsid binding capacity. Our results showed that following viral infection, eqMx2 changes its original cytoplasmic location and accumulates at the nuclear envelope, where it binds to the viral capsid and blocks the nuclear entry of reverse-transcribed proviral DNAs. In contrast, huMxB does not bind to the EIAV capsid and shows no EIAV restriction effect. These studies expand our understanding of the function of the equine Mx2 protein.

Double-stranded-RNA-specific adenosine deaminase 1 (ADAR1) is proposed to contribute to the adaptation of equine infectious anemia virus from horses to donkeys.

Equine infectious anemia virus (EIAV) is a member of the genus Lentivirus of the family Retroviridae. Horses are the most susceptible equids to EIAV infection and are therefore the primary hosts of this virus. In contrast, infected donkeys do not develop clinically active equine infectious anemia (EIA). This phenomenon is similar to what has been observed with HIV-1, which fails to induce AIDS in non-human primates. Interestingly, Shen et al. developed a donkey-tropic pathogenic virus strain (EIAVDV117, DV117) by serially passaging a horse-tropic pathogenic strain, EIAVLN40 (LN40), in donkeys. LN40, which was generated by passaging a field isolate in horses, displayed enhanced virulence in horses but caused no clinical symptoms in donkeys. Infection with DV117 induced acute EIA in nearly 100 % of donkeys. Genomic analysis of DV117 revealed a significantly higher frequency of A-to-G substitutions when compared to LN40. Furthermore, detailed analysis of dinucleotide editing showed that A-to-G mutations had a preference for 5'TpA and 5'ApA. These results strongly implicated the activity of the adenosine deaminase, ADAR1, in this type of mutation. Further investigation demonstrated that overexpression of donkey ADAR1 increased A-to-G mutations within the genome of EIAV. Together with our previous finding that multiple mutations in multiple genes are generated in DV117 during its adaptation from horses to donkeys, the present study suggests that ADAR1-induced A-to-G mutations occur during virus adaption to related new hosts contributing to the alteration of EIAV host tropism.

Equine viperin restricts equine infectious anemia virus replication by inhibiting the production and/or release of viral Gag, Env, and receptor via distortion of the endoplasmic reticulum.

UNLABELLED: Viperin is an endoplasmic reticulum (ER)-associated multifunctional protein that regulates virus replication and possesses broad antiviral activity. In many cases, viperin interferes with the trafficking and budding of viral structural proteins by distorting the membrane transportation system. The lentivirus equine infectious anemia virus (EIAV) has been studied extensively. In this study, we examined the restrictive effect of equine viperin (eViperin) on EIAV replication and investigated the possible molecular basis of this restriction to obtain insights into the effect of this cellular factor on retroviruses. We demonstrated that EIAV infection of primary equine monocyte-derived macrophages (eMDMs) upregulated the expression of eViperin. The overexpression of eViperin significantly inhibited the replication of EIAV in eMDMs, and knockdown of eViperin transcription enhanced the replication of EIAV in eMDMs by approximately 45.8%. Further experiments indicated that eViperin restricts EIAV at multiple steps of viral replication. The overexpression of eViperin inhibited EIAV Gag release. Both the α-helix domain and radical S-adenosylmethionine (SAM) domain were required for this activity. However, the essential motifs in SAM were different from those reported for the inhibition of HIV-1 Gag by human viperin. Furthermore, eViperin disrupted the synthesis of both EIAV Env and receptor, which consequently inhibited viral production and entry, respectively, and this disruption was dependent on the eViperin α-helix domain. Using immunofluorescence assays and electron microscopy, we demonstrated that the α-helix domain is responsible for the distortion of the endoplasmic reticulum (ER). Finally, EIAV did not exhibit counteracting eViperin at the protein level. IMPORTANCE: In previous studies, viperin was indicated as restricting virus replications primarily by the inhibition of virus budding. Here, we show that viperin may have multiple antiviral mechanisms, including the reduction of EIAV Gag budding and Env expression, and these activities are dependent on different viperin domains. We especially demonstrate that the overexpression of viperin inhibits EIAV entry by decreasing the level of virus receptor. Therefore, viperin restriction of viruses is determined largely by the dependence of virus on the cellular membrane transportation system.

TRIMe7-CypA, an alternative splicing isoform of TRIMCyp in rhesus macaque, negatively modulates TRIM5α activity.

The existence of innate, host-specific restriction factors is a major obstacle to the development of nonhuman primate models for AIDS studies, and TRIM5α is one of the most important of these restriction factors. In recent years, a TRIM5 chimeric gene that was retrotransposed by a cyclophilin A (CypA) cDNA was identified in certain macaque species. The TRIM5α-CypA fusion protein, TRIMCyp, which was expressed in these monkeys, had lost its restriction ability toward HIV-1. We previously found that TRIMe7-CypA, an alternative splicing isoform of the TRIMCyp transcripts, was expressed in pig-tailed and rhesus macaques but absent in long-tailed macaques. In this study, the anti-HIV-1 activity of TRIMe7-CypA in the rhesus macaque (RhTRIMe7-CypA) was investigated. The over-expression of RhTRIMe7-CypA in CrFK, HeLa and HEK293T cells did not restrict the infection or replication of an HIV-1-GFP reporter virus in these cells. As a positive control, rhesus (rh)TRIM5α strongly inhibited the reporter virus. Intriguingly, the anti-HIV-1 activity of RhTRIM5α was significantly reduced in a dose-dependent manner by the co-repression of RhTRIMe7-CypA. Our data indicate that although the RhTRIMe7-CypA isoform does not appear to restrict HIV-1, it may act as a negative modulator of TRIM family proteins, presumably by competitive inhibition.

Avian ANP32A incorporated in avian influenza A virions promotes interspecies transmission by priming early viral replication in mammals.

Species-specific differences in acidic nuclear phosphoprotein 32 family member A (ANP32A) determine the restriction of avian-signature polymerase in mammalian cells. Mutations that evade this restriction, such as PB2-E627K, are frequently acquired when avian influenza A viruses jump from avian hosts to mammalian hosts. However, the mechanism underlying this adaptation process is still unclear. Here, we report that host factor ANP32 proteins can be incorporated into influenza viral particles through combination with the viral RNA polymerase (vPol) and then transferred into targeted cells where they support virus replication. The packaging of the ANP32 proteins into influenza viruses is dependent on their affinity with the vPol. Avian ANP32A (avANP32A) delivered by avian influenza A virions primes early viral replication in mammalian cells, thereby favoring the downstream interspecies transmission event by increasing the total amount of virus carrying adaptive mutations. Our study clarifies one role of avANP32A where it is used by avian influenza virus to help counteract the restriction barrier in mammals.

The TRIMCyp genotype in four species of macaques in China.

The tripartite motif protein (TRIM)5α/CypA fusion protein TRIMCyp in Old World monkeys is generally considered unable to restrict HIV-1 replication. Monkeys with TRIMCyp can serve as a unique animal model for studies of HIV-1 infection. The present study investigated the distribution and expression status of TRIMCyp in four species of macaques originating from China and its borderlands: pigtail macaques (Macaca nemestrina), rhesus macaques (Macaca mulatta), long-tailed macaques (Macaca fascicularis), and Tibetan macaques (Macaca thibetana). The results revealed that the frequencies of the TRIMCyp genotype were significantly different among different species and even within different populations of the same species. Interestingly, the TRIMCyp genotype was more prevalent among macaques originating from Yunnan and surrounding regions than those from other regions of China. Importantly, TRIMCyp individuals were first identified in Chinese M. mulatta originating from Yunnan, although multiple earlier studies failed to find CypA retrotransposition in this subspecies. Furthermore, TRIMe7-CypA, one of the splicing isoforms of the TRIMCyp transcript was expressed in M. nemestrina and M. mulatta but not M. fascicularis. The intra- and interspecies polymorphisms in the deduced TRIMCyp amino acid sequences of these macaques were also analyzed. Taken together, the data in this study provide important information about the genomic background of TRIMCyp among major species of Chinese macaques.

Development and validation of a predictive model for major complications after extracorporeal shockwave lithotripsy in patients with ureteral stones: based on a large prospective cohort.

The risk factors of complications after SWL are not well characterized. Therefore, based on a large prospective cohort, we aimed to develop and validate a nomogram for predicting major complications after extracorporeal shockwave lithotripsy (SWL) in patients with ureteral stones. The development cohort included 1522 patients with ureteral stones who underwent SWL between June 2020 and August 2021 in our hospital. Five hundred and fifty-three patients with ureteral stones participated in the validation cohort from September 2020 to April 2022. The data were prospectively recorded. Backward stepwise selection was applied using the likelihood ratio test with Akaike's information criterion as the stopping rule. The efficacy of this predictive model was assessed concerning its clinical usefulness, calibration, and discrimination. Finally, 7.2% (110/1522) of patients in the development cohort and 8.7% (48/553) of those in the validation cohort suffered from major complications. We identified five predictive factors for major complications: age, gender, stone size, Hounsfield unit of stone, and hydronephrosis. This model showed good discrimination with an area under the receiver operating characteristic curves of 0.885 (0.872-0.940) and good calibration (P = 0.139). The decision curve analysis showed that the model was clinically valuable. In this large prospective cohort, we found that older age, female gender, higher Hounsfield unit, size, and grade of hydronephrosis were risk predictors of major complications after SWL. This nomogram will be helpful in preoperative risk stratification to provide individualized treatment recommendations for each patient. Furthermore, early identification and appropriate management of high-risk patients may decrease postoperative morbidity.

E2F3 induces DNA damage repair, stem-like properties and therapy resistance in breast cancer.

Therapy resistance is a major hurdle to the treatment of human malignant tumors. Both DNA damage repair and stem-like properties contribute to chemoresistance and radioresistance. E2F transcription factor 3 (E2F3) is overexpressed in breast cancer tissues, and promotes proliferation of breast cancer cells. Higher E2F3 level is associated with shorter survival of breast cancer patients. Functional studies further showed that E2F3 promotes S-phage entry, DNA replication, DNA damage repair and stem-like properties. Accordingly, E2F3 knockdown sensitizes breast cancer cells to DNA-damaging agents Adriamycin, Cisplatin, Olaparib and X-ray. Forkhead box M1 (FOXM1) is a downstream molecule of E2F3 signaling, mediating the effects of E2F3 on breast cancer cells. In an m6A methyltransferase METTL14-dependent manner, YTH RNA binding protein F2 (YTHDF2) increase E2F3 mRNA stability and expression, promotes DNA damage repair and induces therapy resistance. These data demonstrate that YTHDF2-E2F3 pathway is a novel target to overcome chemoresistance and radioresistance in breast cancer.