Highlights d Phosphoproteomics analysis of SARS-CoV-2-infected cells uncovers signaling rewiring d Infection promotes host p38 MAPK cascade activity and shutdown of mitotic kinases d Infection stimulates CK2-containing filopodial protrusions with budding virus d Kinase activity analysis identifies potent antiviral drugs and compounds

Heart injury has been reported in up to 20% of COVID-19 patients, yet the cause of myocardial histopathology remains unknown. Here, using an established in vivo hamster model, we demonstrate that SARS-CoV-2 can be detected in cardiomyocytes of infected animals. Furthermore, we found damaged cardiomyocytes in hamsters and COVID-19 autopsy samples. To explore the mechanism, we show that both human pluripotent stem cell-derived cardiomyocytes (hPSC-derived CMs) and adult cardiomyocytes (CMs) can be productively infected by SARS-CoV-2, leading to secretion of the monocyte chemoattractant cytokine CCL2 and subsequent monocyte recruitment. Increased CCL2 expression and monocyte infiltration was also observed in the hearts of infected hamsters. Although infected CMs suffer damage, we find that the presence of macrophages significantly reduces SARS-CoV-2 infected CMs. Overall, our study provides direct evidence that SARS-CoV-2 infects CMs in vivo and suggests a mechanism of immune-cell infiltration and histopathology in heart tissues of COVID-19 patients.

Pharmacological immune checkpoint blockade has revolutionized oncological therapies, and its remarkable success has sparked interest in expanding checkpoint inhibitor therapy in infectious diseases. Herein, we evaluated the efficacy of programmed cell death protein 1 (PD-1) blockade in a murine invasive pulmonary aspergillosis model. We found that, compared with isotype-treated infected control mice, anti–PD-1–treated mice had improved survival, reduced fungal burden, increased lung concentrations of proinflammatory cytokines and neutrophil-attracting chemokines, and enhanced pulmonary leukocyte accumulation. Furthermore, combined treatment with anti–PD-1 and caspofungin resulted in a significant survival benefit compared with caspofungin or anti–PD-1 therapy alone, indicating a synergistic effect between PD-1 inhibitors and immunomodulatory antifungal agents.

Type I interferon (IFN) signaling in fetal tissues causes developmental abnormalities and fetal demise. Although pathogens that infect fetal tissues can induce birth defects through the local production of type I IFN, it remains unknown why systemic IFN generated during maternal infections only rarely causes fetal developmental defects. Here, we report that activation of the guanine nucleotide–binding protein–coupled estrogen receptor 1 (GPER1) during pregnancy is both necessary and sufficient to suppress IFN signaling and does so disproportionately in reproductive and fetal tissues. Inactivation of GPER1 in mice halted fetal development and promoted fetal demise, but only in the context of maternal inflammation. Thus, GPER1 is a central regulator of IFN signaling during pregnancy that allows dynamic antiviral responses in maternal tissues while also preserving fetal health.

We examined the mutagenic specificity of the widely used antibiotic ciprofloxacin (CPR), which displays weak to moderate mutagenic activity in several bacteria and generates short in-frame deletions in rpoB in Staphylococcus aureus. To determine the spectrum of mutations in a system where any gene knockout would result in a recovered mutant, including frameshifts and both short and long deletions, we examined CPR-induced mutations in the thymidylate synthase-encoding thyA gene. Here, any mutation resulting in loss of thymidylate synthase activity generates trimethoprim (Trm) resistance. We found that deletions and insertions in all three reading frames predominated in the spectrum. They tend to be short deletions and cluster in two regions, one being a GC-rich region with potential extensive secondary structures. We also exploited the well-characterized rpoB-Rif r system in Escherichia coli to determine that cells grown in the presence of sublethal doses of CPR not only induced short inframe deletions in rpoB, but also generated base substitution mutations resulting from induction of the SOS system. Some of the specific point mutations prominent in the spectrum of a strain that overproduces the dinB-encoded Pol IV were also present after growth in CPR. However, these mutations disappeared in CPR-treated dinB mutants, whereas the deletions remained. Moreover, CPR-induced deletions also occurred in a strain lacking all three SOS-induced polymerases. We discuss the implications of these findings for the consequences of overuse of CPR and other antibiotics. Several bactericidal antibiotics have been reported to have low to moderate mutagenic activity when used at subinhibitory or sublethal concentrations (1-14), usually ranging from 3-to 8-fold over background levels of spontaneous mutations (with one exception [7]). In particular, ciprofloxacin (CPR) and its close derivative norfloxacin (NOR) display mutagenic activity in different detector systems (1-14). The mutagenic properties can result in an increase in the appearance of resistant mutants (1, 2, 4, 5). A previous study of CPR-induced mutations in the rpoB gene of Staphylococcus aureus detected short in-frame deletions (5). However, the rpoB system cannot detect out-of-frame deletions or insertions or in-frame deletions or insertions of more than 21 bp, since the integrity of the RNA polymerase must remain intact. Here, we have undertaken a study of the types of mutations resulting from treatment with CPR in Escherichia coli using the thyATrm r system, which detects trimethoprim (Trm)-resistant mutants that result from any mutations inactivating the thyA gene (15), including large or small deletions or additions, both in frame and out of frame. We also used the E. coli rpoB-Rif r system, which monitors mutations leading to rifampin (Rif) resistance (16-23), since the system is so extensively characterized that the spectra of different mutagenic pathways leave telltale fingerprints. This allows us to separate effects of CPR itself from those emanating from the ...

In the experimental procedures of the main text and in the supplemental information, the authors have now corrected the source of Golden Syrian hamsters to ''Charles River'' instead of ''Jackson Laboratory'' (the latter of which mistakenly appeared in the original version). The authors apologize for the confusion caused.

We show that trimethoprim (TMP), an antibiotic in current use, displays a strong synergistic effect on mutagenesis in Escherichia coli when paired with the base analog 2-aminopurine (2AP), resulting in a 35-fold increase in mutation frequencies in the rpoB-Rifr system. Combination therapies are often employed both as antibiotic treatments and in cancer chemotherapy. However, mutagenic effects of these combinations are rarely examined. An analysis of the mutational spectra of TMP, 2AP, and their combination indicates that together they trigger a response via an alteration in deoxynucleoside triphosphate (dNTP) ratios that neither compound alone can trigger. A similar, although less strong, response is seen with the frameshift mutagen ICR191 and 2AP. These results underscore the need for testing the effects on mutagenesis of combinations of antibiotics and chemotherapeutics.

While bacterial dysbiosis has been associated with increased HIV-1 transmission risk, little is known about direct associations between HIV-1 and bacteria. This study evaluated HIV-1 interactions with bacteria through glycan-binding lectins that affect virus infectivity. The Streptococcal Siglec-like lectin SLBR-N, which is part of the fimbriae shrouding the bacteria surface and recognizes α2,3 sialyated O-linked glycans, was noted for the ability to enhance HIV-1 infectivity in the context of cell-free infection and cell-to-cell transfer. SLBR-N was demonstrated to capture HIV-1 virions, bind to O-glycans on HIV-1 Env, and augment CD4 binding to Env. Other SLBRs recognizing distinct O-glycans also enhanced HIV-1 infectivity, albeit to lower extents, whereas N-glycan-binding bacterial lectins FimH and Msl had no effect. Enhancing effects were recapitulated with O-glycan-binding plant lectins. Hence, this study highlights the potential contribution of O-glycans in promoting HIV-1 infection through the exploitation of O-glycan-binding lectins from commensal bacteria at the mucosa.