T-type calcium channels blockers inhibit HSV-2 infection at the late stage of genome replication

Repurposing oxiconazole to inhibit STING trafficking via OSBP and alleviate autoimmune pathology in Trex1-/- mice

The cGAS-STING pathway is a critical component of the innate immune response to cytosolic DNA, driving the production of type I interferons (IFNs) and pro-inflammatory cytokines. However, excessive activation of this pathway is associated with various autoimmune and inflammatory diseases. In this study, we evaluated the regulation of FDA-approved azole antifungal drugs on the cGAS-STING pathway. Among these drugs, oxiconazole, miconazole, and itraconazole demonstrate significant inhibitory effects, with oxiconazole showing the strongest activity. Our data demonstrates that oxiconazole significantly suppressed type I IFN production and downstream inflammatory responses in macrophages and fibroblasts stimulated with synthetic DNA or infected with HSV-1. Mechanistically, oxiconazole hindered STING trafficking via oxysterol-binding protein OSBP. Using the Listeria monocytogenes infection model and the Trex1-/- mouse disease model, both representing in vivo models of inflammation driven by excessive cGAS-STING activation, we demonstrate that oxiconazole enhanced bacterial clearance and reduced tissue damage in the Listeria monocytogenes infection model. Moreover, oxiconazole treatment significantly alleviated multi-organ inflammation and normalized aberrant IFN responses in the Trex1-/- autoimmune disease mouse model. These findings highlight the potential of oxiconazole as a promising therapeutic agent for STING-driven autoimmune and inflammatory diseases.

Lipopolysaccharide-induced DNA damage response activates DNA-PKcs to drive actin cytoskeleton disruption and cardiac microvascular dysfunction in endotoxemia

Rationale: Sepsis-induced cardiomyopathy is characterized by microvascular injury, which is linked to lipopolysaccharide (LPS)-induced DNA damage response (DDR). This study investigates the role of DNA-PKcs, a key enzyme in the DDR pathway, in driving actin disruption and microvascular dysfunction following LPS exposure. Methods: We analyzed diverse transcriptomic datasets from septic human and murine models using bioinformatics tools to assess DDR pathway activation, correlations, and prognosis. In vivo, LPS-challenged mice were treated with inhibitors of DNA-PKcs or mitochondrial fission, and we evaluated cardiac function, microvascular integrity, mitochondrial status, and actin polymerization. Results: Bioinformatic analyses consistently revealed significant activation of the DDR pathway and upregulation of key genes across diverse septic models. Notably, elevated DDR pathway activity was significantly correlated with poor 28-day survival in human sepsis patients. Single-cell analysis localized this DDR gene upregulation predominantly to cardiac endothelial cells (ECs), fibroblasts, and macrophages during sepsis. Within septic capillary ECs, DDR pathway activity scores strongly correlated spatially and functionally with heightened mitochondrial fission and cytoskeletal remodeling pathway activities. In vivo experiments confirmed that LPS induced severe systolic and diastolic dysfunction, microvascular damage, and mitochondrial fragmentation, as well as significant actin depolymerization. Inhibition of DNA-PKcs with NU7441 markedly attenuated all these LPS-induced pathologies, improving cardiac function, preserving microvascular structure, preventing mitochondrial fragmentation, and normalizing related gene expression and actin cytoskeleton stability. Additionally, inhibiting mitochondrial fission with Mdivi-1 significantly ameliorated LPS-induced cardiac dysfunction and microvascular injury. Conclusions: Our findings suggest that LPS triggers a DNA-PKcs-dependent DDR that promotes mitochondrial fragmentation and actin disruption, particularly in cardiac ECs, contributing to sepsis-induced cardiomyopathy. Targeting DNA-PKcs or mitochondrial fission may hold therapeutic potential for the treatment of sepsis-induced cardiomyopathy.

Nuclear damage-induced DNA damage response coupled with IFI16-driven ECM remodeling underlies dilated cardiomyopathy

Rationale: Dilated cardiomyopathy (DCM) is a severe cardiac condition characterized by ventricular dilation and systolic dysfunction, often leading to heart failure. While the DNA damage response (DDR) pathway is increasingly implicated in DCM pathogenesis, the precise mechanisms linking DDR activation to specific pathological features like adverse extracellular matrix (ECM) remodeling and fibrosis remain poorly understood. Interferon-inducible protein 16 (IFI16), a known DNA sensor involved in DDR and inflammatory signaling, emerges as a potential mediator in this process. This study aimed to investigate the role of the DDR-IFI16 axis in DCM, specifically exploring its connection to ECM dysregulation and cardiac dysfunction, and to evaluate its potential as a therapeutic target. Methods: W This study integrated bioinformatics analyses of human cardiac transcriptomic datasets with experimental validation in a doxorubicin-induced murine DCM model. Cardiac function was assessed by echocardiography. Key molecular pathways were investigated using qPCR, ELISA, and enrichment analyses. Mechanistic roles were tested via pharmacological DDR inhibition in vivo and targeted IFI16 siRNA knockdown in vitro, followed by analysis of fibrosis, cell viability, and cytotoxicity markers. Results: Bioinformatic analyses consistently revealed activation of DDR and cytosolic DNA sensing pathways across human iPSC-CM models and ex vivo DCM heart tissue. WGCNA identified a key gene module strongly associated with DCM, co-enriched for DDR, DNA replication, and ECM/TGF-β signaling pathways. Single-cell RNA-seq analysis confirmed significant IFI16 upregulation in human DCM samples. High IFI16 expression strongly correlated with pathways governing 'Extracellular matrix organization' and key fibrotic genes. Experimental validation in the doxorubicin mouse model confirmed DDR activation. Crucially, in vivo treatment with the DDR inhibitor NU7441 significantly attenuated IFI16 upregulation, ameliorated cardiac dysfunction, and decreased cardiac fibrosis markers. Complementarily, in vitro knockdown of IFI16 significantly reduced pro-fibrotic markers, increased cell viability, and decreased cell injury. Conclusions: Our findings delineate a novel pathogenic axis in DCM where nuclear stress-induced DDR activation drives the upregulation of the DNA sensor IFI16. IFI16 acts as a critical mediator linking DDR signaling to pathological ECM remodeling and fibrosis. Pharmacological inhibition of the upstream DDR pathway effectively mitigates IFI16 induction, attenuates cardiac fibrosis, and improves cardiac function. This study identifies the DDR-IFI16-ECM remodeling axis as a crucial contributor to DCM pathogenesis and highlights its potential as a therapeutic target for mitigating adverse cardiac remodeling and dysfunction.

Verapamil inhibits respiratory syncytial virus infection by regulating Ca2+ influx

AIMS

The study evaluated the antiviral effect of Verapamil against respiratory syncytial virus (RSV) and investigated its underlying mechanism.

MATERIALS AND METHODS

RSV-infected BALB/c mice were treated with Verapamil. Body weight, survival rates, viral load, lung damage, inflammatory factors, and the expression of RSV fusion (F) protein were analyzed. In cellular studies, intracellular Ca2+ and viral titers were measured in the presence of Verapamil, Calcium Chloride, and EGTA. A time-of-addition assay assessed the antiviral effect of Verapamil.

KEY FINDINGS

Mice infected with RSV and treated with Verapamil exhibited a significant decrease in weight loss, an increase in survival rates, and reductions in viral titers, RSV F protein expression, inflammatory responses, and lung tissue injury. Verapamil reduced intracellular calcium levels, which correlated with reduced viral titers. The addition of calcium chloride reversed the anti-viral effects mediated by Verapamil, while EGTA potentiated them. The antiviral activity of Verapamil was observed during the early phase of RSV infection, likely by blocking Ca2+ channels and inhibiting virus replication.

SIGNIFICANCE

Verapamil effectively inhibits RSV infection by blocking calcium channels and reducing intracellular calcium levels, thereby impeding viral replication. Thus, Verapamil shows promise as a treatment for RSV.

CFTR Inhibitors Display Antiviral Activity against Herpes Simplex Virus

The cystic fibrosis transmembrane conductance regulator (CFTR), a cAMP-dependent Cl- channel, is closely associated with multiple pathogen infections, such as SARS-CoV-2. However, whether the function of the CFTR is involved in herpes simplex virus (HSV) infection has not been reported. To evaluate the association of CFTR activity with HSV infection, the antiviral effect of CFTR inhibitors in epithelial cells and HSV-infected mice was tested in this study. The data showed that treatment with CFTR inhibitors in different concentrations, Glyh-101 (5-20 μM), CFTRi-172 (5-20 μM) and IOWH-032 (5-20 μM), or the gene silence of the CFTR could suppress herpes simplex virus 1 (HSV-1) and herpes simplex virus 2 (HSV-2) replication in human HaCaT keratinocytes cells, and that a CFTR inhibitor, Glyh-101 (10-20 μM), protected mice from HSV-1 and HSV-2 infection. Intracellular Cl- concentration ([Cl-]i) was decreased after HSV infection via the activation of adenylyl cyclase (AC)-cAMP signaling pathways. CFTR inhibitors (20 μM) increased the reduced [Cl-]i caused by HSV infection in host epithelial cells. Additionally, CFTR inhibitors reduced the activity and phosphorylation of SGK1 in infected cells and tissues (from the eye and vagina). Our study found that CFTR inhibitors can effectively suppress HSV-1 and HSV-2 infection, revealing a previously unknown role of CFTR inhibitors in HSV infection and suggesting new perspectives on the mechanisms governing HSV infection in host epithelial cells, as well as leading to potential novel treatments.

Kv1.3-induced hyperpolarization is required for efficient Kaposi's sarcoma-associated herpesvirus lytic replication

Kaposi's sarcoma-associated herpesvirus (KSHV) is an oncogenic herpesvirus that is linked directly to the development of Kaposi's sarcoma. KSHV establishes a latent infection in B cells, which can be reactivated to initiate lytic replication, producing infectious virions. Using pharmacological and genetic silencing approaches, we showed that the voltage-gated K+ channel Kv1.3 in B cells enhanced KSHV lytic replication. The KSHV replication and transcription activator (RTA) protein increased the abundance of Kv1.3 and led to enhanced K+ channel activity and hyperpolarization of the B cell membrane. Enhanced Kv1.3 activity promoted intracellular Ca2+ influx, leading to the Ca2+-driven nuclear localization of KSHV RTA and host nuclear factor of activated T cells (NFAT) proteins and subsequently increased the expression of NFAT1 target genes. KSHV lytic replication and infectious virion production were inhibited by Kv1.3 blockers or silencing. These findings highlight Kv1.3 as a druggable host factor that is key to the successful completion of KSHV lytic replication.

Diltiazem HCl suppresses porcine reproductive and respiratory syndrome virus infection in susceptible cells and in swine

Porcine reproductive and respiratory syndrome virus (PRRSV) is a pathogen for swine, resulting in substantial economic losses to the swine industry. However, there has been little success in developing effective vaccines or drugs for PRRSV control. In the present study, we discovered that Diltiazem HCl, an inhibitor of L-type Ca2+ channel, effectively suppresses PRRSV replication in MARC-145, PK-15CD163 and PAM cells in dose-dependent manner. Furthermore, it demonstrates a broad-spectrum activity against both PRRSV-1 and PRRSV-2 strains. Additionally, we explored the underlying mechanisms and found that Diltiazem HCl -induced inhibition of PRRSV associated with regulation of calcium ion homeostasis in susceptible cells. Moreover, we evaluated the antiviral effects of Diltiazem HCl in PRRSV-challenged piglets, assessing rectal temperature, viremia, and gross and microscopic lung lesions. Our results indicate that Diltiazem HCl treatment alleviates PRRSV-induced rectal temperature spikes, pulmonary pathological changes, and serum viral load. In conclusion, our data suggest that Diltiazem HCl could serve as a novel therapeutic drug against PRRSV infection.

Benidipine impairs innate immunity converting sublethal to lethal infections in a murine model of spotted fever rickettsiosis

Spotted fever group rickettsiae are tick-borne obligate intracellular bacteria that infect microvascular endothelial cells. Humans and mammalian infection results in endothelial cell barrier dysfunction and increased vascular permeability. We previously demonstrated that treatment of Rickettsia parkeri-infected cells with the calcium channel blocker benidipine significantly delayed vascular barrier permeability. Thus, we hypothesized that benidipine, known to be safe and effective for other clinical processes, could reduce rickettsia-induced vascular permeability in vivo in an animal model of spotted fever rickettsiosis. Based on liver, lung and brain vascular FITC-dextran extravasation studies, benidipine did not reliably impact vascular permeability. However, it precipitated a deleterious effect on responses to control sublethal R. parkeri infection. Animals treated with benidipine alone had no clinical signs or changes in histopathology and splenic immune cell distributions. Benidipine-treated infected animals had marked increases in tissue and blood bacterial loads, more extensive inflammatory histopathologic injury, and changes in splenic architecture and immune cell distributions potentially reflecting diminished Ca2+ signaling, reduced innate immune cell activation, and loss of rickettsial propagation control. Impaired T cell activation by R. parkeri antigen in the presence of benidipine was confirmed in vitro with the use of NKT cell hybridomas. The unexpected findings stand in stark contrast to recent discussions of the benefits of calcium channel blockers for viral infections and chronic infectious or inflammatory diseases. A role for calcium channel blockers in exacerbation of human rickettsiosis and acute inflammatory infections should be evaluated by a retrospective review of patient's outcomes and medications.

TRPV4 channel is involved in HSV-2 infection in human vaginal epithelial cells through triggering Ca2+ oscillation

Herpes simplex virus (HSV) infection induces a rapid and transient increase in intracellular calcium concentration ([Ca2+]i), which plays a critical role in facilitating viral entry. T-type calcium channel blockers and EGTA, a chelate of extracellular Ca2+, suppress HSV-2 infection. But the cellular mechanisms mediating HSV infection-activated Ca2+ signaling have not been completely defined. In this study we investigated whether the TRPV4 channel was involved in HSV-2 infection in human vaginal epithelial cells. We showed that the TRPV4 channel was expressed in human vaginal epithelial cells (VK2/E6E7). Using distinct pharmacological tools, we demonstrated that activation of the TRPV4 channel induced Ca2+ influx, and the TRPV4 channel worked as a Ca2+-permeable channel in VK2/E6E7 cells. We detected a direct interaction between the TRPV4 channel protein and HSV-2 glycoprotein D in the plasma membrane of VK2/E6E7 cells and the vaginal tissues of HSV-2-infected mice as well as in phallic biopsies from genital herpes patients. Pretreatment with specific TRPV4 channel inhibitors, GSK2193874 (1-4 μM) and HC067047 (100 nM), or gene silence of the TRPV4 channel not only suppressed HSV-2 infectivity but also reduced HSV-2-induced cytokine and chemokine generation in VK2/E6E7 cells by blocking Ca2+ influx through TRPV4 channel. These results reveal that the TRPV4 channel works as a Ca2+-permeable channel to facilitate HSV-2 infection in host epithelial cells and suggest that the design and development of novel TRPV4 channel inhibitors may help to treat HSV-2 infections.

A Systematic Review of Second-Line Treatments in Antiviral Resistant Strains of HSV-1, HSV-2, and VZV

Drug-resistant variants of herpes simplex viruses (HSV) have been reported that are not effectively treated with first-line antiviral agents. The objective of this study was to evaluate available literature on the possible efficacy of second-line treatments in HSV and the use of second-line treatments in HSV strains that are resistant to first-line treatments. Following Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines, a final search was conducted in six databases on November 5, 2021 for all relevant literature using terms related to antiviral resistance, herpes, and HSV. Eligible manuscripts were required to report the presence of an existing or proposed second-line treatment for HSV-1, HSV-2, or varicella zoster virus (VZV); have full-text English-language access; and potentially reduce the rate of antiviral resistance. Following screening, 137 articles were included in qualitative synthesis. Of the included studies, articles that examined the relationship between viral resistance to first-line treatments and potential second-line treatments in HSV were included. The Cochrane risk-of-bias tool for randomized trials was used to assess risk of bias. Due to the heterogeneity of study designs, a meta-analysis of the studies was not performed. The dates in which accepted studies were published spanned from 2015-2021. In terms of sample characteristics, the majority (72.26%) of studies used Vero cells. When looking at the viruses on which the interventions were tested, the majority (84.67%) used HSV-1, with (34.31%) of these studies reporting testing on resistant HSV strains. Regarding the effectiveness of the proposed interventions, 91.97% were effective as potential managements for resistant strains of HSV. Of the papers reviewed, nectin in 2.19% of the reviews had efficacy as a second-line treatments in HSV, amenamevir in 2.19%, methanol extract in 2.19%, monoclonal antibodies in 1.46%, arbidol in 1.46%, siRNA swarms in 1.46%, Cucumis melo sulfated pectin in 1.46%, and components from Olea europeae in 1.46%. In addition to this griffithsin in 1.46% was effective, Morus alba L. in 1.46%, using nucleosides in 1.46%, botryosphaeran in 1.46%, monoterpenes in 1.46%, almond skin extracts in 1.46%, bortezomib in 1.46%, flavonoid compounds in 1.46%, andessential oils were effective in 1.46%, but not effective in 0.73%. The available literature reviewed consistently supports the existence and potentiality of second-line treatments for HSV strains that are resistant to first-line treatments. Immunocompromised patients have been noted to be the population most often affected by drug-resistant variants of HSV. Subsequently, we found that HSV infections in this patient population are challenging to manage clinically effectively. The goal of this systematic review is to provide additional information to patients on the potentiality of second-line treatment in HSV strains resistant to first-line treatments, especially those who are immunocompromised. All patients, whether they are immunocompromised or not, deserve to have their infections clinically managed in a manner supported by comprehensive research. This review provides necessary information about treatment options for patients with resistant HSV infections and their providers.

Inhibitory activity of aqueous extracts of tea compositions, individual ingredients for their preparation and some plants against replication of Herpes simplex virus type 2 <i>in vitro</i>

Aim. In vitro analysis of the inhibitory activity of aqueous extracts of tea compositions, plant raw materials and as well as plants from different families against replication of Herpes simplex virus type 2.

Material and Methods. The viral strain MS of HSV‐2 was passivated on Vero cell culture. Antiviral (inhibitory) activity of aqueous extracts was studied in vitro according to the classical scheme of neutralization (inactivation) of the virus.

Results. For comparison we used control samples of aqueous extracts of Chaga mushroom (Inonotus obliquus) and grass of Alchemilla vulgaris L. with EC50 equal to 21.36±3.92 and 39.67±8.75 µg/ml (for dry raw materials) versus 103  PFU/ml HSV‐2. As a result the prevailing activity (from 15.25±3.92 to 1.71±0.54 µg/ml) was identified for extracts of tea compositions based on black and green tea, as well as individual ingredients for their composition – black tea, leaves of Mentha piperita L.,  flowers  of  Lavandula  angustifolia  Mill. and  clove  spices  (Syzygium aromaticum L.). Extracts obtained from plants that are not part of tea compositions of interest are fermented leaves of Epilobium angustifolium L. (Onagraceae) and grass of two species Euphorbia (E. pilosa L. and E. esula  L.,  Euphorbiaceae)  with  inhibitory  activity  at  concentrations  of 10.675±1.96; 2.29±0.57 and 1.71±0.54 µg/ml, respectively.

Conclusion. The results presented can become the basis for the search for individual biologically active substances of plant origin that inhibit HSV‐2 replication as well as for the development of effective medicines in the form of tea beverages and/or formulations for topical use to reduce relapses of chronic herpes.

Ion channels and ions as therapeutic targets and strategies for herpes simplex virus infection

Herpes simplex virus (HSV) is a highly contagious virus that cannot be completely cured currently. Existing treatment methods are mainly nucleoside antiviral drugs, and the emergence of drug-resistant strains severely limits their use. There is an urgent need to discover antiviral drugs that act on new targets. Ion channels, a class of cellular proteins with a wide range of functions, have become critical host factors for a wide variety of viral infections. Ion channel blockers have been shown to have antiviral activity. In this study, we discuss the role of ion channels and ions in the HSV life cycle, and the potential of targeting ion channels as a novel, pharmacologically safe and wide-range antiviral treatment option.

Modulation of Adaptive Immunity and Viral Infections by Ion Channels

Most cellular functions require of ion homeostasis and ion movement. Among others, ion channels play a crucial role in controlling the homeostasis of anions and cations concentration between the extracellular and intracellular compartments. Calcium (Ca2+) is one of the most relevant ions involved in regulating critical functions of immune cells, allowing the appropriate development of immune cell responses against pathogens and tumor cells. Due to the importance of Ca2+ in inducing the immune response, some viruses have evolved mechanisms to modulate intracellular Ca2+ concentrations and the mobilization of this cation through Ca2+ channels to increase their infectivity and to evade the immune system using different mechanisms. For instance, some viral infections require the influx of Ca2+ through ionic channels as a first step to enter the cell, as well as their replication and budding. Moreover, through the expression of viral proteins on the surface of infected cells, Ca2+ channels function can be altered, enhancing the pathogen evasion of the adaptive immune response. In this article, we review those ion channels and ion transporters that are essential for the function of immune cells. Specifically, cation channels and Ca2+ channels in the context of viral infections and their contribution to the modulation of adaptive immune responses.

Inhibition of Severe Acute Respiratory Syndrome Coronavirus 2 Replication by Hypertonic Saline Solution in Lung and Kidney Epithelial Cells

An unprecedented global health crisis has been caused by a new virus called severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). We performed experiments to test if a hypertonic saline solution was capable of inhibiting virus replication. Our data show that 1.2% NaCl inhibited virus replication by 90%, achieving 100% of inhibition at 1.5% in the nonhuman primate kidney cell line Vero, and 1.1% of NaCl was sufficient to inhibit the virus replication by 88% in human epithelial lung cell line Calu-3. Furthermore, our results indicate that the inhibition is due to an intracellular mechanism and not to the dissociation of the spike SARS-CoV-2 protein and its human receptor. NaCl depolarizes the plasma membrane causing a low energy state (high ADP/ATP concentration ratio) without impairing mitochondrial function, supposedly associated with the inhibition of the SARS-CoV-2 life cycle. Membrane depolarization and intracellular energy deprivation are possible mechanisms by which the hypertonic saline solution efficiently prevents virus replication in vitro assays.