PLoS Pathogens最新文献

Middle East respiratory syndrome coronavirus (MERS-CoV) is an emerging coronavirus that can cause zoonotic disease in humans with lethal severe viral pneumonia. Dromedary camels are the source of zoonotic infection. As of November 2025, MERS-CoV has resulted in a total of 2630 reported cases, 37% of these being fatal. The number of reported human cases has been on a decreasing trend since 2016 and reached a nadir during the COVID-19 pandemic. The reason for the reduction of cases is unclear and may be multifactorial. We hypothesized that mutations accumulating in the virus spike protein may have reduced zoonotic potential. Here, we investigate the impact of recently emerged virus spike-protein mutations on virus replication competence using pseudoviruses and replication-competent recombinant viruses. We found that virus spike variants detected in 2019 and some from 2023 show a reduced cell entry, lower viral replication and reduced fitness in human primary alveolar epithelial cells and multiple cell lines. All the MERS-CoV spikes tested showed a cell-entry pathway preference via the cell-surface TMPRSS2 route. Mechanistically, we showed the V530A mutation in the 2019 spike sequence had a reduced human DPP4 binding phenotype. Our data highlighted MERS-CoV spike mutations can modulate viral fitness in human cells and provide new insights to understand recent MERS epidemiology.

Epigenetic suppression and durable silencing of HIV represent a promising strategy to achieve ART-free remission, consistent with the "block and lock" HIV cure paradigm. BRD4 is a host epigenetic reader and plays a critical role in HIV transcriptional regulation. We previously identified ZL0580, a first-in-class BRD4-selective small molecule distinct from the pan-BET inhibitor JQ1, which induces HIV epigenetic suppression. However, detailed molecular mechanisms, pharmacokinetics (PK), and in vivo HIV-suppressive efficacy of ZL0580 remain undefined. Here, we show that ZL0580 selectively targets BRD4 bromodomain 1 (BD1) through interaction with a key glutamic acid residue (E151), as determined by structural modeling and mutagenesis. Transcriptomic profiling by RNA-seq reveals that ZL0580 and JQ1 induce opposing gene expression programs, consistent with their distinct effects on HIV proviral transcription and latency. In a humanized mouse model of HIV infection, ZL0580 monotherapy, or in combination with ART, potently suppressed active HIV replication, reducing the plasma viremia to nearly undetectable levels, and delayed viral rebound following treatment interruption. Collectively, these findings establish ZL0580 as an epigenetic suppressor of HIV in vivo and provide proof-of-concept for its potential as a "block and lock" HIV cure candidate, warranting further optimization and development.

[This corrects the article DOI: 10.1371/journal.ppat.1012860.].

[This corrects the article DOI: 10.1371/journal.ppat.1009440.].

Chlamydiae are obligate intracellular bacteria that inhibit mitochondrial apoptosis to maintain integrity of the host cell. We have previously reported that a chlamydial outer membrane β-barrel protein, OmpA, can during ectopic expression inhibit mitochondrial apoptosis through direct interaction with the BCL-2-family effectors BAX and BAK. We here show that OmpA from Chlamydia trachomatis (Ctr) uses membrane vesicles for its delivery to the outer mitochondrial membrane during Ctr infection. Using a number of imaging and fractionation techniques, we show that OmpA during infection reaches mitochondria and is inserted into mitochondrial membranes. Chlamydia derived vesicles (CDV) from Ctr-infected cells contained OmpA as well as other outer membrane proteins and LPS. When added to uninfected cells, CDVs fused with mitochondrial membranes, causing the interaction of OmpA with BAK and the cytosolic retro-translocation of BAX. CDV addition to uninfected cells also protected the cells against apoptosis. We previously showed that OmpA works in co-ordination with VDAC2 to block apoptosis and here propose a structural model of this BAK inhibition by OmpA that reenacts the inhibition of BAK by VDAC2. The results provide evidence that OmpA from Chlamydia, as well as the structurally similar ortholog from the related Simkania, specifically exploits its relationship to mitochondrial porins to protect the infected cell against apoptosis and to enable intracellular growth of the bacteria in human cells.

Porcine astrovirus (PAstV) is an important and widespread pathogen in swine, linked to diarrheal outbreaks and extraintestinal disease. How PAstV enters host cells has remained unclear, and no cellular factor has been defined for PAstV entry. Here, a genome-wide CRISPR-Cas9 loss-of-function screen in porcine epithelial cells identifies Annexin A1 (ANXA1) as a host factor that facilitates PAstV entry. Genetic ablation or pharmacological/antibody blockade of ANXA1 reduces binding, lowers early viral RNA and capsid signals, and delays the rise of progeny, whereas re-expression restores susceptibility. Biochemical assays and surface plasmon resonance indicate a direct interaction between ANXA1 and the acidic C-terminal domain of the PAstV ORF2 capsid protein, and imaging shows ANXA1 co-localizes with incoming particles at the cell surface and supports attachment and uptake. Loss of ANXA1 does not alter infection by the non-astrovirus panel tested, indicating selectivity for PAstV under our conditions. Notably, infection is reduced but not abolished in ANXA1-deficient cells, consistent with additional entry factors acting alongside ANXA1. These findings position ANXA1 as an entry cofactor for PAstV and provide a mechanistic basis to refine models of astrovirus host-cell recognition.

Tuberculosis (TB) kills an estimated 1.25 million people annually and is the leading cause of death in people with HIV (PWH) (1). The CD4+ T helper (Th) populations play significant roles in protective immunity to Mycobacterium tuberculosis (Mtb) and are essential hosts for HIV pathogenesis. Emerging evidence in blood and gastrointestinal mucosa of PWH suggests that, among Th cells, Th17 and Th22 may be preferentially depleted during HIV infection. Targeting of Th17 and Th22 cells by HIV could pose important and poorly understood risks for Mtb containment in those with co-infection. Mtb-driven activation of Th17 and Th22 immunity may also contribute to HIV proliferation and persistence. We employed a humanized mouse model of co-infection to assess changes in Th17 and Th22 frequency and function due to infection with HIV, Mtb, or both. In infected mice, Th17 cells were the predominant host for HIV in spleen and shown to be a source of HIV replication in pulmonary TB granulomas. Th17 cells were increased in lung of mice with TB or TB-HIV. Conversely, Th22 cells were reduced in mice with HIV or TB-HIV. Mtb infection increased the viral load in lungs of co-infected mice while HIV suppressed the pulmonary Th17 family cytokine response to Mtb including IL-6, IL-22, IL-23, and IL-1β. Differential transcriptome assessment demonstrated that HIV co-infection disrupted Th17 pathways activated by Mtb in lung. Overall, these results suggest that HIV may compromise Th22 immunity and exploit Th17 cells to promote viral pathogenesis in the setting of Mtb and HIV co-infection.

The latency of human immunodeficiency virus type 1 (HIV-1) is a major barrier to achieving an HIV-1 cure, as antiretroviral therapy does not target the latent virus. Virus-host interactions play an essential role in various stages of the HIV-1 lifecycle. Exploring the interaction between host factors and HIV-1 infection is critical for developing new HIV-1 treatment strategies. Yes-associated protein (YAP) is a key co-transcription factor in the Hippo signaling pathway, which regulates the occurrence and development of various diseases, including cellular metabolism, cancer, immunity, and viral infection. In this study, we first confirmed that YAP gene expression in patients with acquired immune deficiency syndrome (AIDS) was significantly lower than that in the healthy control group, as determined using the GEO2R online tool. Furthermore, YAP was identified as a negative regulator of HIV-1 transcription by mediating K33- and K48-linked ubiquitination and proteasomal degradation of Tat. Here, we further confirmed that the YAP TAD domain recruited ubiquitin-like with PHD and RING finger domain 1 (UHRF1) to mediate Tat's ubiquitination and degradation by the screening of the BioGRID database combined with IP-MS analysis. The conserved lysine residues K28, K29, and K41 on Tat were critical acceptor sites for ubiquitination and proteasomal degradation. Our findings revealed that YAP promotes the suppression of HIV-1 transcription and the maintenance of HIV-1 latency, providing novel insights into virus-host interactions for regulating HIV-1 latency.

Antibiotic tolerance is the ability of bacteria to survive normally lethal doses of antibiotics for extended time periods. Clinically significant Enterobacterales, for example, can exhibit high tolerance to the last-resort antibiotic meropenem. Meropenem tolerance is associated with formation of cell wall-deficient spheroplasts that readily recover to rod shape and normal growth upon removal of the antibiotic. Both the true prevalence of tolerance, and genetic mechanisms underlying it, remain poorly understood. Here, we find that meropenem tolerance is widespread among clinical Enterobacterales. Using forward genetics, we uncover tolerance factors in a hypertolerant isolate of the ESKAPE pathogen Klebsiella pneumoniae. We find that multiple mechanisms contribute to tolerance, and that cell envelope stress responses (PhoPQ, CpxPRA, Rcs phosphorelay and OmpR/EnvZ) collectively promote spheroplast stability and recovery, while the lytic transglycosylase MltB counteracts it. Our data indicate that tolerance is widespread among clinical isolates, and that outer membrane maintenance is a key factor promoting survival of tolerant K. pneumoniae.