A novel goose-origin Tembusu virus exhibits pathogenicity in day-old chicks with evidence of direct contact transmission.

In late 2020, an outbreak of Tembusu virus (TMUV)-associated disease occurred in a 45-day-old white Roman geese flock in Taiwan. Here, we present the identification and isolation of a novel goose-origin TMUV strain designated as NTU/C225/2020. The virus was successfully isolated using minimal-pathogen-free duck embryos. Phylogenetic analysis of the polyprotein gene showed that NTU/C225/2020 clustered together with the earliest isolates from Malaysia and was most closely related to the first Taiwanese TMUV strain, TP1906. Genomic analysis revealed significant amino acid variations among TMUV isolates in NS1 and NS2A protein regions. In the present study, we characterized the NTU/C225/2020 culture in duck embryos, chicken embryos, primary duck embryonated fibroblasts, and DF-1 cells. All host systems were susceptible to NTU/C225/2020 infection, with observable lesions. In addition, animal experiments showed that the intramuscular inoculation of NTU/C225/2020 resulted in growth retardation and hyperthermia in day-old chicks. Gross lesions in the infected chicks included hepatomegaly, hyperemic thymus, and splenomegaly. Viral loads and histopathological damage were displayed in various tissues of both inoculated and naïve co-housed chicks, confirming the direct chick-to-chick contact transmission of TMUV. This is the first in vivo study of a local TMUV strain in Taiwan. Our findings provide essential information for TMUV propagation and suggest a potential risk of disease outbreak in chicken populations.

GAGE mediates radio resistance in cervical cancers via the regulation of chromatin accessibility.

Radiotherapy (RT) resistance is a major cause of treatment failure in cancers that use definitive RT as their primary treatment modality. This study identifies the cancer/testis (CT) antigen G antigen (GAGE) as a mediator of radio resistance in cervical cancers. Elevated GAGE expression positively associates with de novo RT resistance in clinical samples. GAGE, specifically the GAGE12 protein variant, confers RT resistance through synemin-dependent chromatin localization, promoting the association of histone deacetylase 1/2 (HDAC1/2) to its inhibitor actin. This cumulates to elevated histone 3 lysine 56 acetylation (H3K56Ac) levels, increased chromatin accessibility, and improved DNA repair efficiency. Molecular or pharmacological disruption of the GAGE-associated complex restores radiosensitivity. Molecularly, this study demonstrates the role of GAGE in the regulation of chromatin dynamics. Clinically, this study puts forward the utility of GAGE as a pre-screening biomarker to identify poor responders at initial diagnosis and the therapeutic potential of agents that target GAGE and its associated complex in combination with radiotherapy to improve outcomes.

Development and characterization of mouse monoclonal antibodies targeting to distinct epitopes of Zika virus envelope protein for specific detection of Zika virus.

The recent Zika virus (ZIKV) epidemic poses a serious threat to global health due to its association with microcephaly and congenital diseases in newborns and neurological complications and Guillain-Barré syndrome in adults. However, the majority of people infected with ZIKV do not develop symptoms. The platforms aimed to specifically diagnose ZIKV infection are needed for patient care and public health surveillance. In the study, four ZIKV envelope (E) protein-specific monoclonal antibodies (mAbs) (A1, B1, C1, and 9E-1) have been developed by using the conventional mAb technology. The binding epitopes of mAbs A1, B1, C1, and 9E-1 are located at E(238-257), E(410-431), E(258-277), and E(340-356), respectively. mAb 9E-1 performs 1.4- to 47-fold strong affinity to ZIKV E protein compared to another three mAbs. mAbs A1, C1, and 9E-1 do not have cross-reactivity against the recombinant E proteins of dengue virus serotypes 2, 3, and 4. Although these four mAbs do not have ZIKV neutralizing activity, mAbs B1 and 9E-1 have been developed as the lateral flow immunochromatographic assay for specific detection of ZIKV E protein and virions. KEY POINTS: • The mAbs targeting to the regions of E(238-257), E(410-431), E(258-277), and E(340-356) do not have ZIKV neutralizing activity. • The binding epitope of mAb 9E-1 is highly specific to ZIKV E protein. • mAbs B1 and 9E-1 can bind to ZIKV virions and have been developed as the lateral flow immunochromatographic assay.

Outcome of Different Approaches to Reduce Urinary Tract Infection in Patients With Spinal Cord Lesions: A Systematic Review.

Neurogenic bladder disorders are common among patients with spinal cord lesions, which often result in upper and lower urinary tract complications. Urinary tract infection has remained the most frequent type of infection in this population. Our aim is to review systematically the literature on the outcome of different intervention methods to reduce urinary tract infection incidence. A literature search was conducted in the database of Medline, PubMed, Embase, and Scopus. After screening 1559 articles, 42 were included in this review. The intervention methods can be categorized into the four following groups: (1) indwelling catheterization and intermittent catheterization, (2) medications, (3) surgery, and (4) others. Intermittent catheterization is still the most recommended treatment for persons with spinal cord lesions. Hydrophilic catheters are more suitable for adults than children because of complex handling. Bladder management with spontaneous voiding is initially considered for infants and toddlers with spina bifida. Antibiotics treatment should be based on the results of urine cultures. Shortening the course of antibiotics treatment can reduce its adverse effects but may increase urinary tract infection recurrence. Because botulinum toxin injections and bladder surgery can improve urodynamic function, both are conducive toward lowering urinary tract infection incidence.

BLMP-1/Blimp-1 regulates the spatiotemporal cell migration pattern in C. elegans.

Spatiotemporal regulation of cell migration is crucial for animal development and organogenesis. Compared to spatial signals, little is known about temporal signals and the mechanisms integrating the two. In the Caenorhabditis elegans hermaphrodite, the stereotyped migration pattern of two somatic distal tip cells (DTCs) is responsible for shaping the gonad. Guidance receptor UNC-5 is necessary for the dorsalward migration of DTCs. We found that BLMP-1, similar to the mammalian zinc finger transcription repressor Blimp-1/PRDI-BF1, prevents precocious dorsalward turning by inhibiting precocious unc-5 transcription and is only expressed in DTCs before they make the dorsalward turn. Constitutive expression of blmp-1 when BLMP-1 would normally disappear delays unc-5 transcription and causes turn retardation, demonstrating the functional significance of blmp-1 down-regulation. Correct timing of BLMP-1 down-regulation is redundantly regulated by heterochronic genes daf-12, lin-29, and dre-1, which regulate the temporal fates of various tissues. DAF-12, a steroid hormone receptor, and LIN-29, a zinc finger transcription factor, repress blmp-1 transcription, while DRE-1, the F-Box protein of an SCF ubiquitin ligase complex, binds to BLMP-1 and promotes its degradation. We have therefore identified a gene circuit that integrates the temporal and spatial signals and coordinates with overall development of the organism to direct cell migration during organogenesis. The tumor suppressor gene product FBXO11 (human DRE-1 ortholog) also binds to PRDI-BF1 in human cell cultures. Our data suggest evolutionary conservation of these interactions and underscore the importance of DRE-1/FBXO11-mediated BLMP-1/PRDI-BF1 degradation in cellular state transitions during metazoan development.

Hemojuvelin modulates iron stress during acute kidney injury: improved by furin inhibitor.

AIMS: Free iron plays an important role in the pathogenesis of acute kidney injury (AKI) via the formation of hydroxyl radicals. Systemic iron homeostasis is controlled by the hemojuvelin-hepcidin-ferroportin axis in the liver, but less is known about this role in AKI. RESULTS: By proteomics, we identified a 42 kDa soluble hemojuvelin (sHJV), processed by furin protease from membrane-bound hemojuvelin (mHJV), in the urine during AKI after cardiac surgery. Biopsies from human and mouse specimens with AKI confirm that HJV is extensively increased in renal tubules. Iron overload enhanced the expression of hemojuvelin-hepcidin signaling pathway. The furin inhibitor (FI) decreases furin-mediated proteolytic cleavage of mHJV into sHJV and augments the mHJV/sHJV ratio after iron overload with hypoxia condition. The FI could reduce renal tubule apoptosis, stabilize hypoxic induced factor-1, prevent the accumulation of iron in the kidney, and further ameliorate ischemic-reperfusion injury. mHJV is associated with decreasing total kidney iron, secreting hepcidin, and promoting the degradation of ferroportin at AKI, whereas sHJV does the opposite. INNOVATION: This study suggests the ratio of mHJV/sHJV affects the iron deposition during acute kidney injury and sHJV could be an early biomarker of AKI. CONCLUSION: Our findings link endogenous HJV inextricably with renal iron homeostasis for the first time, add new significance to early predict AKI, and identify novel therapeutic targets to reduce the severity of AKI using the FI.

Suppression of Klotho expression by protein-bound uremic toxins is associated with increased DNA methyltransferase expression and DNA hypermethylation.

The expression of the renoprotective antiaging gene Klotho is decreased in uremia. Recent studies suggest that Klotho may be a tumor suppressor, and its expression may be repressed by DNA hypermethylation in cancer cells. Here we investigated the effects and possible mechanisms by which Klotho expression is regulated during uremia in uninephrectomized B-6 mice given the uremic toxins indoxyl sulfate or p-cresyl sulfate. Cultured human renal tubular HK2 cells treated with these toxins were used as an in vitro model. Injections of indoxyl sulfate or p-cresyl sulfate increased their serum concentrations, kidney fibrosis, CpG hypermethylation of the Klotho gene, and decreased Klotho expression in renal tubules of these mice. The expression of DNA methyltransferases 1, 3a, and 3b isoforms in HK2 cells treated with indoxyl sulfate or p-cresyl sulfate was significantly increased. Specific inhibition of DNA methyltransferase isoform 1 by 5-aza-2'-deoxycytidine caused demethylation of the Klotho gene and increased Klotho expression in vitro. Thus, inhibition of Klotho gene expression by uremic toxins correlates with gene hypermethylation, suggesting that epigenetic modification of specific genes by uremic toxins may be an important pathological mechanism of disease.

Mechanism of gate opening in the 20S proteasome by the proteasomal ATPases.

Substrates enter the cylindrical 20S proteasome through a gated channel that is regulated by the ATPases in the 19S regulatory particle in eukaryotes or the homologous PAN ATPase complex in archaea. These ATPases contain a conserved C-terminal hydrophobic-tyrosine-X (HbYX) motif that triggers gate opening upon ATP binding. Using cryo-electron microscopy, we identified the sites in the archaeal 20S where PAN's C-terminal residues bind and determined the structures of the gate in its closed and open forms. Peptides containing the HbYX motif bind to 20S in the pockets between neighboring alpha subunits where they interact with conserved residues required for gate opening. This interaction induces a rotation in the alpha subunits and displacement of a reverse-turn loop that stabilizes the open-gate conformation. This mechanism differs from that of PA26/28, which lacks the HbYX motif and does not cause alpha subunit rotation. These findings demonstrated how the ATPases' C termini function to facilitate substrate entry.

Docking of the proteasomal ATPases' carboxyl termini in the 20S proteasome's alpha ring opens the gate for substrate entry.

The 20S proteasome functions in protein degradation in eukaryotes together with the 19S ATPases or in archaea with the homologous PAN ATPase complex. These ATPases contain a conserved C-terminal hydrophobic-tyrosine-X motif (HbYX). We show that these residues are essential for PAN to associate with the 20S and open its gated channel for substrate entry. Upon ATP binding, these C-terminal residues bind to pockets between the 20S's alpha subunits. Seven-residue or longer peptides from PAN's C terminus containing the HbYX motif also bind to these sites and induce gate opening in the 20S. Gate opening could be induced by C-terminal peptides from the 19S ATPase subunits, Rpt2, and Rpt5, but not by ones from PA28/26, which lack the HbYX motif and cause gate opening by distinct mechanisms. C-terminal residues in the 19S ATPases were also shown to be critical for gating and stability of 26S proteasomes. Thus, the C termini of the proteasomal ATPases function like a "key in a lock" to induce gate opening and allow substrate entry.

Immune selection for altered antigen processing leads to cytotoxic T lymphocyte escape in chronic HIV-1 infection.

Mutations within cytotoxic T lymphocyte (CTL) epitopes impair T cell recognition, but escape mutations arising in flanking regions that alter antigen processing have not been defined in natural human infections. In human histocompatibility leukocyte antigen (HLA)-B57+ HIV-infected persons, immune selection pressure leads to a mutation from alanine to proline at Gag residue 146 immediately preceding the NH2 terminus of a dominant HLA-B57-restricted epitope, ISPRTLNAW. Although N-extended wild-type or mutant peptides remained well-recognized, mutant virus-infected CD4 T cells failed to be recognized by the same CTL clones. The A146P mutation prevented NH2-terminal trimming of the optimal epitope by the endoplasmic reticulum aminopeptidase I. These results demonstrate that allele-associated sequence variation within the flanking region of CTL epitopes can alter antigen processing. Identifying such mutations is of major relevance in the construction of vaccine sequences.