G protein-coupled and ATP-sensitive inwardly rectifying potassium ion channels are essential for HIV entry

Oxidative phosphorylation in HIV-1 infection: impacts on cellular metabolism and immune function

Human Immunodeficiency Virus Type 1 (HIV-1) presents significant challenges to the immune system, predominantly characterized by CD4+ T cell depletion, leading to Acquired Immunodeficiency Syndrome (AIDS). Antiretroviral therapy (ART) effectively suppresses the viral load in people with HIV (PWH), leading to a state of chronic infection that is associated with inflammation. This review explores the complex relationship between oxidative phosphorylation, a crucial metabolic pathway for cellular energy production, and HIV-1, emphasizing the dual impact of HIV-1 infection and the metabolic and mitochondrial effects of ART. The review highlights how HIV-1 infection disrupts oxidative phosphorylation, promoting glycolysis and fatty acid synthesis to facilitate viral replication. ART can exacerbate metabolic dysregulation despite controlling viral replication, impacting mitochondrial DNA synthesis and enhancing reactive oxygen species production. These effects collectively contribute to significant changes in oxidative phosphorylation, influencing immune cell metabolism and function. Adenosine triphosphate (ATP) generated through oxidative phosphorylation can influence the metabolic landscape of infected cells through ATP-detected purinergic signaling and contributes to immunometabolic dysfunction. Future research should focus on identifying specific targets within this pathway and exploring the role of purinergic signaling in HIV-1 pathogenesis to enhance HIV-1 treatment modalities, addressing both viral infection and its metabolic consequences.

Regulatory effects of potassium channel blockers on potassium channel genes upon nervous necrosis virus infection in sevenband grouper Hyporthodus septumfasciatus

Ion channels in fishes regulate the flow of important ions that play an active role in the excitation and transmission of impulses through neuronal cells. Specific housekeeping genes translates into proteins and selectively permeabilize and facilitate ion crossover transmissions. Potassium (K+) channels play a crucial role in a wide range of functions such as cell volume regulation, hormone secretion, synaptic transmission and muscle contraction. The dysfunction of ion channels result in channelopathies, which hinder critical cellular activities. Recent studies have indicated that viral pathogens tend to regulate cellular ion channels for entry into host cells. Hence, the present study aimed to elucidate the role of K+ channels during nervous necrosis virus (NNV) infections in the sevenband grouper (Hyporthodus septumfasciatus). Real-time PCR with the standardized potassium genes revealed the downregulation of potassium two pore domain channel subfamily member - KCNK10, KCNK9, KCNK2, and KCNK1 genes post infection at both 17 °C and 25 °C whereas an upregulation was noted in the case of gill tissues. SMART analysis revealed a transmembrane region in all genes. Multiple sequence alignment using MultAlin and phylogenetic analysis revealed true homology of potassium genes with other higher vertebrates. In vitro and in vivo challenge study of NNV using Tetra ethyl ammonium (TEA) as potential drug showed inverse relation to that of viral replication and a corresponding downregulation of K+ channel gene expression was observed which was further confirmed by an immunofluorescence assay. These findings indicate that K+ channels play a crucial role during viral infection. Moreover, the observed downregulation can be related to rapid endocytosis resulting from recycling endosomes during a viral infection. Hence, further studies are warranted to better understand the role of K+ channel genes during NNV infection.

A cohort-based study of host gene expression: tumor suppressor and innate immune/inflammatory pathways associated with the HIV reservoir size

The major barrier to an HIV cure is the HIV reservoir: latently-infected cells that persist despite effective antiretroviral therapy (ART). There have been few cohort-based studies evaluating host genomic or transcriptomic predictors of the HIV reservoir. We performed host RNA sequencing and HIV reservoir quantification (total DNA [tDNA], unspliced RNA [usRNA], intact DNA) from peripheral CD4+ T cells from 191 ART-suppressed people with HIV (PWH). After adjusting for nadir CD4+ count, timing of ART initiation, and genetic ancestry, we identified two host genes for which higher expression was significantly associated with smaller total DNA viral reservoir size, P3H3 and NBL1, both known tumor suppressor genes. We then identified 17 host genes for which lower expression was associated with higher residual transcription (HIV usRNA). These included novel associations with membrane channel (KCNJ2, GJB2), inflammasome (IL1A, CSF3, TNFAIP5, TNFAIP6, TNFAIP9, CXCL3, CXCL10), and innate immunity (TLR7) genes (FDR-adjusted q<0.05). Gene set enrichment analyses further identified significant associations of HIV usRNA with TLR4/microbial translocation (q = 0.006), IL-1/NRLP3 inflammasome (q = 0.008), and IL-10 (q = 0.037) signaling. Protein validation assays using ELISA and multiplex cytokine assays supported these observed inverse host gene correlations, with P3H3, IL-10, and TNF-α protein associations achieving statistical significance (p<0.05). Plasma IL-10 was also significantly inversely associated with HIV DNA (p = 0.016). HIV intact DNA was not associated with differential host gene expression, although this may have been due to a large number of undetectable values in our study. To our knowledge, this is the largest host transcriptomic study of the HIV reservoir. Our findings suggest that host gene expression may vary in response to the transcriptionally active reservoir and that changes in cellular proliferation genes may influence the size of the HIV reservoir. These findings add important data to the limited host genetic HIV reservoir studies to date.

Exploitation of ATP-sensitive potassium ion (KATP) channels by HPV promotes cervical cancer cell proliferation by contributing to MAPK/AP-1 signalling

Persistent infection with high-risk human papillomaviruses (HPVs) is the causal factor in multiple human malignancies, including >99% of cervical cancers and a growing proportion of oropharyngeal cancers. Prolonged expression of the viral oncoproteins E6 and E7 is necessary for transformation to occur. Although some of the mechanisms by which these oncoproteins contribute to carcinogenesis are well-characterised, a comprehensive understanding of the signalling pathways manipulated by HPV is lacking. Here, we present the first evidence to our knowledge that the targeting of a host ion channel by HPV can contribute to cervical carcinogenesis. Through the use of pharmacological activators and inhibitors of ATP-sensitive potassium ion (KATP) channels, we demonstrate that these channels are active in HPV-positive cells and that this activity is required for HPV oncoprotein expression. Further, expression of SUR1, which forms the regulatory subunit of the multimeric channel complex, was found to be upregulated in both HPV+ cervical cancer cells and in samples from patients with cervical disease, in a manner dependent on the E7 oncoprotein. Importantly, knockdown of SUR1 expression or KATP channel inhibition significantly impeded cell proliferation via induction of a G1 cell cycle phase arrest. This was confirmed both in vitro and in in vivo tumourigenicity assays. Mechanistically, we propose that the pro-proliferative effect of KATP channels is mediated via the activation of a MAPK/AP-1 signalling axis. A complete characterisation of the role of KATP channels in HPV-associated cancer is now warranted in order to determine whether the licensed and clinically available inhibitors of these channels could constitute a potential novel therapy in the treatment of HPV-driven cervical cancer.

The role of extracellular ATP and P2X receptors in the pathogenesis of HIV-1

Human Immunodeficiency Virus Type 1 (HIV-1) causes a chronic, incurable infection associated with chronic inflammation despite virologic suppression on antiretroviral therapy (ART). This chronic inflammation underlies significant comorbidities, including cardiovascular disease, neurocognition decline, and malignancies. The mechanisms of chronic inflammation have been attributed, in part, to the role of extracellular ATP and P2X-type purinergic receptors that sense damaged or dying cells and undergo signaling responses to activate inflammation and immunomodulation. This review describes the current literature on the role of extracellular ATP and P2X receptors in HIV-1 pathogenesis, describing the known intersection with the HIV-1 life cycle in mediating immunopathogenesis and neuronal disease. The literature supports key roles for this signaling mechanism in cell-to-cell communication and in activating transcriptional changes that impact the inflammatory state leading to disease progression. Future studies must characterize the numerous functions of ATP and P2X receptors in HIV-1 pathogenesis to inform future therapeutic targeting.

The role of ion channels in immune-related diseases

Ion channel is an integral membrane protein that allows the permeation of charge ions across hydrophobic phospholipid membranes, including plasma membranes and organelle membranes (such as mitochondria, endoplasmic reticulum and vacuoles), which are widely distributed in various cells and tissues, such as cardiomyocytes, smooth muscle cells, and nerve cells. Ion channels establish membrane potential by regulating ion concentration and membrane potential. Membrane potential plays an important role in cells. Studies have shown that ion channels play a role in a number of immune-related diseases caused by functional defects in ion channels on immune or non-immune cells in major human organs, usually affecting specific organs or multiple organs. The present review discusses the relationship between ion channels and immune diseases in major organs of the human body.

The role of Pannexin-1 channels and extracellular ATP in the pathogenesis of the human immunodeficiency virus

Only recently, the role of large ionic channels such as Pannexin-1 channels and Connexin hemichannels has been implicated in several physiological and pathological conditions, including HIV infection and associated comorbidities. These channels are in a closed stage in healthy conditions, but in pathological conditions including HIV, Pannexin-1 channels and Connexin hemichannels become open. Our data demonstrate that acute and chronic HIV infection induces channel opening (Pannexin and Connexin channels), ATP release into the extracellular space, and subsequent activation of purinergic receptors in immune and non-immune cells. We demonstrated that Pannexin and Connexin channels contribute to HIV infection and replication, the long-term survival of viral reservoirs, and comorbidities such as NeuroHIV. Here, we discuss the available data to support the participation of these channels in the HIV life cycle and the potential therapeutic approach to prevent HIV-associated comorbidities.

Ion Channels as Therapeutic Targets for Viral Infections: Further Discoveries and Future Perspectives

Ion channels play key roles in almost all facets of cellular physiology and have emerged as key host cell factors for a multitude of viral infections. A catalogue of ion channel-blocking drugs have been shown to possess antiviral activity, some of which are in widespread human usage for ion channel-related diseases, highlighting new potential for drug repurposing. The emergence of ion channel–virus interactions has also revealed the intriguing possibility that channelopathies may explain some commonly observed virus induced pathologies. This field is rapidly evolving and an up-to-date summary of new discoveries can inform future perspectives. We herein discuss the role of ion channels during viral lifecycles, describe the recently identified ion channel drugs that can inhibit viral infections, and highlight the potential contribution of ion channels to virus-mediated disease.

Identification of potassium and calcium channel inhibitors as modulators of polyomavirus endosomal trafficking

During virus entry, members of the Polyomaviridae transit the endolysosomal network en route to the endoplasmic reticulum (ER), from which degraded capsids escape into the cytoplasm and enter the nucleus. Emerging evidence suggests that viruses require both endosomal acidification and the correct ionic balance of K⁺ and Ca²⁺ ions in endosomes for correct virus trafficking and genome release. Here, using two polyomaviruses with different capsid architectures, namely Simian virus 40 (SV40) and Merkel cell polyomavirus (MCPyV), we describe methods to rapidly quantify virus infection using IncuCyte ZOOM imaging analysis, and use this system to investigate the role of both K⁺ and Ca²⁺ channels during the early stages of virus entry. Using broad spectrum blockers of both K⁺ and Ca²⁺ channels to specifically target host cell ion channel functionality, we show that MCPyV, but not SV40 can be inhibited by K⁺ channel modulators, whilst both viruses are restricted by the broad spectrum Ca²⁺ channel inhibitor verapamil. Using a panel of more specific Ca²⁺ blockers, we show that both MCPyV and SV40 are dependent on the activity of two-pore Ca²⁺ channels (TPCs), as the TPC-specific blocker tetrandrine prevented capsid disassembly and nuclear transport required for virus entry. We therefore reveal a novel target to restrict the entry of polyomaviruses, which given the known role of TPCs during endolysosomal-ER fusion, is likely to be applicable to other viruses that transit this pathway.

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We describe novel high-throughput assays to study SV40 and MCPyV infection.

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MCPyV, but not SV40, is sensitive to K⁺ channel inhibition.

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Verapamil inhibits MCPyV and SV40 infection.

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Tetrandrine is a potent inhibitor of MCPyV and SV40 infection.

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Two-pore channel 1/2 activity is essential for polyomavirus entry.