Tag: NK cells

Upregulation of olfactory receptors and neuronal-associated genes highlights complex immune and neuronal dysregulation in Long COVID patients

Abstract:

A substantial portion of patients infected with SARS-CoV-2 experience prolonged complications, known as Long COVID (LC). A subset of these patients exhibits the most debilitating symptoms, similar to those defined in Myalgic Encephalomyelitis/Chronic Fatigue Syndrome (ME/CFS). We performed bulk RNA sequencing (RNAseq) on the whole blood of LC with ME/CFS, at least 12 months post-onset of the acute disease, and compared them with controls.

We found that LC patients had a distinct transcriptional profile compared to controls. Key findings include the upregulation of genes involved in immune dysregulation and neuronal development, such as Fezf2, BRINP2, HOXC12, MEIS2, ZFHX3, and RELN. These genes are linked to neuroinflammatory responses, cognitive impairments, and hematopoietic disturbances, suggesting ongoing neurological and immune disturbances in LC patients. RELN, encoding the Reelin protein, was notably elevated in LC patients, potentially serving as a biomarker for LC pathogenesis due to its role in inflammation and neuronal function.

Immune cell analysis showed altered profiles in LC patients, with increased activated memory CD4 + T cells and neutrophils, and decreased regulatory T cells and NK cells, reflecting immune dysregulation. Changes in cytokine and chemokine expression further underscore the chronic inflammatory state in LC patients. Notably, a unique upregulation of olfactory receptors (ORs) suggest alternative roles for ORs in non-olfactory tissues. Pathway analysis revealed upregulation in ribosomal RNA processing, amino acid metabolism, protein synthesis, cell proliferation, DNA repair, and mitochondrial pathways, indicating heightened metabolic and immune demands. Conversely, downregulated pathways, such as VEGF signaling and TP53 activity, point to impaired tissue repair and cellular stress responses.

Overall, our study underscores the complex interplay between immune and neuronal dysfunction in LC patients, providing insights into potential diagnostic biomarkers and therapeutic targets. Future research is needed to fully understand the roles and interactions of these genes in LC pathophysiology.

Source: Shahbaz S, Rezaeifar M, Syed H, Redmond D, Terveart JWC, Osman M, Elahi S. Upregulation of olfactory receptors and neuronal-associated genes highlights complex immune and neuronal dysregulation in Long COVID patients. Brain Behav Immun. 2024 Nov 28:S0889-1591(24)00721-9. doi: 10.1016/j.bbi.2024.11.032. Epub ahead of print. PMID: 39615603. https://www.sciencedirect.com/science/article/pii/S0889159124007219 (Full text)

Meta-analysis of natural killer cell cytotoxicity in myalgic encephalomyelitis/chronic fatigue syndrome

Abstract:

Reduced natural killer (NK) cell cytotoxicity is the most consistent immune finding in myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS). Meta-analysis of the published literature determined the effect size of the decrement in ME/CFS. Databases were screened for papers comparing NK cell cytotoxicity in ME/CFS and healthy controls. A total of 28 papers and 55 effector:target cell ratio (E:T) data points were collected.

Cytotoxicity in ME/CFS was significantly reduced to about half of healthy control levels, with an overall Hedges’ g of 0.96 (0.75-1.18). Heterogeneity was high but was explained by the range of E:T ratios, different methods, and potential outliers. The outcomes confirm reproducible NK cell dysfunction in ME/CFS and will guide studies using the NK cell model system for pathomechanistic investigations.

Source: Baraniuk JN, Eaton-Fitch N, Marshall-Gradisnik S. Meta-analysis of natural killer cell cytotoxicity in myalgic encephalomyelitis/chronic fatigue syndrome. Front Immunol. 2024 Oct 17;15:1440643. doi: 10.3389/fimmu.2024.1440643. PMID: 39483457; PMCID: PMC11524851. https://pmc.ncbi.nlm.nih.gov/articles/PMC11524851/ (Full text)

Immunometabolic changes and potential biomarkers in CFS peripheral immune cells revealed by single-cell RNA sequencing

Abstract:

The pathogenesis of Myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS) remains unclear, though increasing evidence suggests inflammatory processes play key roles. In this study, single-cell RNA sequencing (scRNA-seq) of peripheral blood mononuclear cells (PBMCs) was used to decipher the immunometabolic profile in 4 ME/CFS patients and 4 heathy controls.

We analyzed changes in the composition of major PBMC subpopulations and observed an increased frequency of total T cells and a significant reduction in NKs, monocytes, cDCs and pDCs. Further investigation revealed even more complex changes in the proportions of cell subpopulations within each subpopulation. Gene expression patterns revealed upregulated transcription factors related to immune regulation, as well as genes associated with viral infections and neurodegenerative diseases.

CD4+ and CD8+ T cells in ME/CFS patients show different differentiation states and altered trajectories, indicating a possible suppression of differentiation. Memory B cells in ME/CFS patients are found early in the pseudotime, indicating a unique subtype specific to ME/CFS, with increased differentiation to plasma cells suggesting B cell overactivity. NK cells in ME/CFS patients exhibit reduced cytotoxicity and impaired responses, with reduced expression of perforin and CD107a upon stimulation. Pseudotime analysis showed abnormal development of adaptive immune cells and an enhanced cell-cell communication network converging on monocytes in particular.

Our analysis also identified the estrogen-related receptor alpha (ESRRA)-APP-CD74 signaling pathway as a potential biomarker for ME/CFS in peripheral blood. In addition, data from the GSE214284 database confirmed higher ESRRA expression in the monocyte cell types of male ME/CFS patients. These results suggest a link between immune and neurological symptoms.

The results support a disease model of immune dysfunction ranging from autoimmunity to immunodeficiency and point to amyloidotic neurodegenerative signaling pathways in the pathogenesis of ME/CFS. While the study provides important insights, limitations include the modest sample size and the evaluation of peripheral blood only.

These findings highlight potential targets for diagnostic biomarkers and therapeutic interventions. Further research is needed to validate these biomarkers and explore their clinical applications in managing ME/CFS.

Source: Sun Y, Zhang Z, Qiao Q, Zou Y, Wang L, Wang T, Lou B, Li G, Xu M, Wang Y, Zhang Z, Hou X, Chen L, Zhao R. Immunometabolic changes and potential biomarkers in CFS peripheral immune cells revealed by single-cell RNA sequencing. J Transl Med. 2024 Oct 11;22(1):925. doi: 10.1186/s12967-024-05710-w. PMID: 39394558. https://translational-medicine.biomedcentral.com/articles/10.1186/s12967-024-05710-w (Full text)

Potential pathophysiological role of the ion channel TRPM3 in myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS) and the therapeutic effect of low-dose naltrexone

Abstract:

Myalgic Encephalomyelitis/Chronic Fatigue Syndrome (ME/CFS) is a debilitating disease with a broad overlap of symptomatology with Post-COVID Syndrome (PCS). Despite the severity of symptoms and various neurological, cardiovascular, microvascular, and skeletal muscular findings, no biomarkers have been identified.

The Transient receptor potential melastatin 3 (TRPM3) channel, involved in pain transduction, thermosensation, transmitter and neuropeptide release, mechanoregulation, vasorelaxation, and immune defense, shows altered function in ME/CFS. Dysfunction of TRPM3 in natural killer (NK) cells, characterized by reduced calcium flux, has been observed in ME/CFS and PCS patients, suggesting a role in ineffective pathogen clearance and potential virus persistence and autoimmunity development.

TRPM3 dysfunction in NK cells can be improved by naltrexone in vitro and ex vivo, which may explain the moderate clinical efficacy of low-dose naltrexone (LDN) treatment. We propose that TRPM3 dysfunction may have a broader involvement in ME/CFS pathophysiology, affecting other organs. This paper discusses TRPM3’s expression in various organs and its potential impact on ME/CFS symptoms, with a focus on small nerve fibers and the brain, where TRPM3 is involved in presynaptic GABA release.

Source: Löhn M, Wirth KJ. Potential pathophysiological role of the ion channel TRPM3 in myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS) and the therapeutic effect of low-dose naltrexone. J Transl Med. 2024 Jul 5;22(1):630. doi: 10.1186/s12967-024-05412-3. PMID: 38970055; PMCID: PMC11227206. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC11227206/ (Full Text)

Novel characterization of endogenous transient receptor potential melastatin 3 ion channels from Gulf War Illness participants

Abstract:

Gulf War Illness (GWI) is a chronic condition characterized by multisystem symptoms that still affect up to one-third of veterans who engaged in combat in the Gulf War three decades ago. The aetiology of GWI is mainly explained by exposure to multiple toxic agents, vaccines, and medications. As there is a significant overlap in symptoms between GWI and Myalgic Encephalomyelitis/Chronic Fatigue Syndrome (ME/CFS), the objective of this study was to investigate a biomarker widely reported in Natural Killer (NK) cells from ME/CFS patients, the Transient Receptor Potential Melastatin 3 (TRPM3) ion channel.

NK cells from 6 healthy controls (HC) and 6 GWI participants were isolated, and TRPM3 function was assessed through whole-cell patch-clamp. As demonstrated by prior studies, NK cells from HC expressed typical TRPM3 function after pharmacomodulation.

In contrast, this pilot investigation demonstrates a dysfunctional TRPM3 in NK cells from GWI participants through application of a TRPM3 agonist and confirmed by a TRPM3 antagonist. There was a significant reduction in TRPM3 function from GWI than results measured in HC. This study provides an unprecedented research field to investigate the involvement of TRP ion channels in the pathomechanism and potential medical interventions to improve GWI quality of life.

Source: Marshall-Gradisnik S, Martini Sasso E, Eaton-Fitch N, Smith P, Baraniuk JN, Muraki K. Novel characterization of endogenous transient receptor potential melastatin 3 ion channels from Gulf War Illness participants. PLoS One. 2024 Jun 25;19(6):e0305704. doi: 10.1371/journal.pone.0305704. PMID: 38917121; PMCID: PMC11198784. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC11198784/ (Full text)

Systems-level temporal immune-metabolic profile in Crimean-Congo hemorrhagic fever virus infection

Abstract:

Crimean-Congo hemorrhagic fever (CCHF) caused by CCHF virus (CCHFV) is one of the epidemic-prone diseases prioritized by the World Health Organisation as public health emergency with an urgent need for accelerated research. The trajectory of host response against CCHFV is multifarious and remains unknown. Here, we reported the temporal spectrum of pathogenesis following the CCHFV infection using genome-wide blood transcriptomics analysis followed by advanced systems biology analysis, temporal immune-pathogenic alterations, and context-specific progressive and postinfection genome-scale metabolic models (GSMM) on samples collected during the acute (T0), early convalescent (T1), and convalescent-phase (T2).

The interplay between the retinoic acid-inducible gene-I-like/nucleotide-binding oligomerization domain-like receptor and tumor necrosis factor signaling governed the trajectory of antiviral immune responses. The rearrangement of intracellular metabolic fluxes toward the amino acid metabolism and metabolic shift toward oxidative phosphorylation and fatty acid oxidation during acute CCHFV infection determine the pathogenicity. The upregulation of the tricarboxylic acid cycle during CCHFV infection, compared to the noninfected healthy control and between the severity groups, indicated an increased energy demand and cellular stress. The upregulation of glycolysis and pyruvate metabolism potentiated energy generation through alternative pathways associated with the severity of the infection.

The downregulation of metabolic processes at the convalescent phase identified by blood cell transcriptomics and single-cell type proteomics of five immune cells (CD4+ and CD8+ T cells, CD14+ monocytes, B cells, and NK cells) potentially leads to metabolic rewiring through the recovery due to hyperactivity during the acute phase leading to post-viral fatigue syndrome.

Source: Ambikan AT, Elaldi N, Svensson-Akusjärvi S, Bagci B, Pektas AN, Hewson R, Bagci G, Arasli M, Appelberg S, Mardinoglu A, Sood V, Végvári Á, Benfeitas R, Gupta S, Cetin I, Mirazimi A, Neogi U. Systems-level temporal immune-metabolic profile in Crimean-Congo hemorrhagic fever virus infection. Proc Natl Acad Sci U S A. 2023 Sep 12;120(37):e2304722120. doi: 10.1073/pnas.2304722120. Epub 2023 Sep 5. PMID: 37669378; PMCID: PMC10500270. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC10500270/ (Full text)

Investigation into the restoration of TRPM3 ion channel activity in post-COVID-19 condition: a potential pharmacotherapeutic target

Abstract:

Introduction: Recently, we reported that post COVID-19 condition patients also have Transient Receptor Potential Melastatin 3 (TRPM3) ion channel dysfunction, a potential biomarker reported in natural killer (NK) cells from Myalgic Encephalomyelitis/Chronic Fatigue Syndrome (ME/CFS) patients. As there is no universal treatment for post COVID-19 condition, knowledge of ME/CFS may provide advances to investigate therapeutic targets. Naltrexone hydrochloride (NTX) has been demonstrated to be beneficial as a pharmacological intervention for ME/CFS patients and experimental investigations have shown NTX restored TRPM3 function in NK cells. This research aimed to: i) validate impaired TRPM3 ion channel function in post COVID-19 condition patients compared with ME/CFS; and ii) investigate NTX effects on TRPM3 ion channel activity in post COVID-19 condition patients.

Methods: Whole-cell patch-clamp was performed to characterize TRPM3 ion channel activity in freshly isolated NK cells of post COVID-19 condition (N = 9; 40.56 ± 11.26 years), ME/CFS (N = 9; 39.33 ± 9.80 years) and healthy controls (HC) (N = 9; 45.22 ± 9.67 years). NTX effects were assessed on post COVID-19 condition (N = 9; 40.56 ± 11.26 years) and HC (N = 7; 45.43 ± 10.50 years) where NK cells were incubated for 24 hours in two protocols: treated with 200 µM NTX, or non-treated; TRPM3 channel function was assessed with patch-clamp protocol.

Results: This investigation confirmed impaired TRPM3 ion channel function in NK cells from post COVID-19 condition and ME/CFS patients. Importantly, PregS-induced TRPM3 currents were significantly restored in NTX-treated NK cells from post COVID-19 condition compared with HC. Furthermore, the sensitivity of NK cells to ononetin was not significantly different between post COVID-19 condition and HC after treatment with NTX.

Discussion: Our findings provide further evidence identifying similarities of TRPM3 ion channel dysfunction between ME/CFS and post COVID-19 condition patients. This study also reports, for the first time, TRPM3 ion channel activity was restored in NK cells isolated from post COVID-19 condition patients after in vitro treatment with NTX. The TRPM3 restoration consequently may re-establish TRPM3-dependent calcium (Ca2+) influx. This investigation proposes NTX as a potential therapeutic intervention and TRPM3 as a treatment biomarker for post COVID-19 condition.

Source: Etianne Martini Sasso, Katsuhiko Muraki, Natalie Eaton-Fitch, Peter Smith, Andrew Jeremijenko, Paul Griffin, Sonya Marshall-Gradisnik. Investigation into the restoration of TRPM3 ion channel activity in post-COVID-19 condition: a potential pharmacotherapeutic target. Front. Immunol., 02 May 2024; Sec. Multiple Sclerosis and Neuroimmunology; Volume 15 – 2024 | https://doi.org/10.3389/fimmu.2024.1264702. https://www.frontiersin.org/journals/immunology/articles/10.3389/fimmu.2024.1264702/full (Full text)

SARS-CoV-2 viral persistence in lung alveolar macrophages is controlled by IFN-γ and NK cells

Abstract:

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) RNA generally becomes undetectable in upper airways after a few days or weeks postinfection. Here we used a model of viral infection in macaques to address whether SARS-CoV-2 persists in the body and which mechanisms regulate its persistence.

Replication-competent virus was detected in bronchioalveolar lavage (BAL) macrophages beyond 6 months postinfection. Viral propagation in BAL macrophages occurred from cell to cell and was inhibited by interferon-γ (IFN-γ). IFN-γ production was strongest in BAL NKG2r+CD8+ T cells and NKG2Alo natural killer (NK) cells and was further increased in NKG2Alo NK cells after spike protein stimulation.

However, IFN-γ production was impaired in NK cells from macaques with persisting virus. Moreover, IFN-γ also enhanced the expression of major histocompatibility complex (MHC)-E on BAL macrophages, possibly inhibiting NK cell-mediated killing. Macaques with less persisting virus mounted adaptive NK cells that escaped the MHC-E-dependent inhibition.

Our findings reveal an interplay between NK cells and macrophages that regulated SARS-CoV-2 persistence in macrophages and was mediated by IFN-γ.

Source: Huot N, Planchais C, Rosenbaum P, Contreras V, Jacquelin B, Petitdemange C, Lazzerini M, Beaumont E, Orta-Resendiz A, Rey FA, Reeves RK, Le Grand R, Mouquet H, Müller-Trutwin M. SARS-CoV-2 viral persistence in lung alveolar macrophages is controlled by IFN-γ and NK cells. Nat Immunol. 2023 Nov 2. doi: 10.1038/s41590-023-01661-4. Epub ahead of print. PMID: 37919524. https://www.nature.com/articles/s41590-023-01661-4 (Full text)

Surveying the Metabolic and Dysfunctional Profiles of T Cells and NK Cells in Myalgic Encephalomyelitis/Chronic Fatigue Syndrome

Abstract:

Millions globally suffer from myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS). The inflammatory symptoms, illness onset, recorded outbreak events, and physiological variations provide strong indications that ME/CFS, at least sometimes, has an infectious origin, possibly resulting in a chronic unidentified viral infection.
Meanwhile, studies exposing generalized metabolic disruptions in ME/CFS have stimulated interest in isolated immune cells with an altered metabolic state. As the metabolism dictates the cellular function, dissecting the biomechanics of dysfunctional immune cells in ME/CFS can uncover states such as exhaustion, senescence, or anergy, providing insights into the consequences of these phenotypes in this disease. Despite the similarities that are seen metabolically between ME/CFS and other chronic viral infections that result in an exhausted immune cell state, immune cell exhaustion has not yet been verified in ME/CFS.
This review explores the evidence for immunometabolic dysfunction in ME/CFS T cell and natural killer (NK) cell populations, comparing ME/CFS metabolic and functional features to dysfunctional immune cell states, and positing whether anergy, exhaustion, or senescence could be occurring in distinct immune cell populations in ME/CFS, which is consistent with the hypothesis that ME/CFS is a chronic viral disease.
This comprehensive review of the ME/CFS immunometabolic literature identifies CD8+ T cell exhaustion as a probable contender, underscores the need for further investigation into the dysfunctional state of CD4+ T cells and NK cells, and explores the functional implications of molecular findings in these immune-cell types. Comprehending the cause and impact of ME/CFS immune cell dysfunction is critical to understanding the physiological mechanisms of ME/CFS, and developing effective treatments to alleviate the burden of this disabling condition.
Source: Maya J. Surveying the Metabolic and Dysfunctional Profiles of T Cells and NK Cells in Myalgic Encephalomyelitis/Chronic Fatigue Syndrome. International Journal of Molecular Sciences. 2023; 24(15):11937. https://doi.org/10.3390/ijms241511937 https://www.mdpi.com/1422-0067/24/15/11937 (Full text)

Altered TRPM7-Dependent Calcium Influx in Natural Killer Cells of Myalgic Encephalomyelitis/Chronic Fatigue Syndrome Patients

Abstract:

Myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS) is a disabling multisystemic condition. The pathomechanism of ME/CFS remains unestablished; however, impaired natural killer (NK) cell cytotoxicity is a consistent feature of this condition. Calcium (Ca2+) is crucial for NK cell effector functions.
Growing research recognises Ca2+ signalling dysregulation in ME/CFS patients and implicates transient receptor potential ion channel dysfunction. TRPM7 (melastatin) was recently considered in the pathoaetiology of ME/CFS as it participates in several Ca2+-dependent processes that are central to NK cell cytotoxicity which may be compromised in ME/CFS. TRPM7-dependent Ca2+ influx was assessed in NK cells isolated from n = 9 ME/CFS patients and n = 9 age- and sex-matched healthy controls (HCs) using live cell fluorescent imaging techniques.
Slope (p < 0.05) was significantly reduced in ME/CFS patients compared with HCs following TRPM7 activation. Half-time of maximal response (p < 0.05) and amplitude (p < 0.001) were significantly reduced in the HCs compared with the ME/CFS patients following TRPM7 desensitisation.
Findings from this investigation suggest that TRPM7-dependent Ca2+ influx is reduced with agonism and increased with antagonism in ME/CFS patients relative to the age- and sex-matched HCs. The outcomes reported here potentially reflect TRPM3 dysfunction identified in this condition suggesting that ME/CFS is a TRP ion channelopathy.
Source: Du Preez S, Eaton-Fitch N, Smith PK, Marshall-Gradisnik S. Altered TRPM7-Dependent Calcium Influx in Natural Killer Cells of Myalgic Encephalomyelitis/Chronic Fatigue Syndrome Patients. Biomolecules. 2023; 13(7):1039. https://doi.org/10.3390/biom13071039 https://www.mdpi.com/2218-273X/13/7/1039 (Full text)