Tag: mouse model

Impact of age and sex on neuroinflammation following SARS-CoV-2 infection in a murine model

Abstract:

Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2), the etiological agent of COVID-19, is known to infect people of all ages and both sexes. Senior populations have the greatest risk of severe COVID-19, and sexual dimorphism in clinical outcomes has been reported. Neurological symptoms are widely observed in COVID-19 patients, with many survivors exhibiting persistent neurological and cognitive impairment. The present study aims to investigate the impact of age and sex on the neuroinflammatory response to SARS-CoV-2 infection using a mouse model. Wild-type C57BL/6J mice were intranasally inoculated with SARS-CoV-2 lineage B.1.351, a variant known to infect mice.

Older male mice exhibited a significantly greater weight loss and higher viral loads in the lung at 3 days post infection. Notably, no viral RNA was detected in the brains of infected mice. Nevertheless, expression of IL-6, TNF-α, and CCL-2 in the lung and brain increased with viral infection. RNA-seq transcriptomic analysis of brains showed that SARS-CoV-2 infection caused significant changes in gene expression profiles, implicating innate immunity, defense response to virus, and cerebrovascular and neuronal functions.

These findings demonstrate that SARS-CoV-2 infection triggers a neuroinflammatory response, despite the lack of detectable virus in the brain. Aberrant activation of innate immune response, disruption of blood-brain barrier and endothelial cell integrity, and suppression of neuronal activity and axonogenesis underlie the impact of SARS-CoV-2 infection on the brain. Understanding the role of these affected pathways in SARS-CoV-2 pathogenesis helps identify appropriate points of therapeutic interventions to alleviate neurological dysfunction observed during COVID-19.

Source: Krishna VD, Chang A, Korthas H, Var SR, Low WC, Li L, Cheeran MC. Impact of age and sex on neuroinflammation following SARS-CoV-2 infection in a murine model. bioRxiv [Preprint]. 2023 Aug 14:2023.08.11.552998. doi: 10.1101/2023.08.11.552998. Update in: Front Microbiol. 2024 Jul 15;15:1404312. doi: 10.3389/fmicb.2024.1404312. PMID: 37645925; PMCID: PMC10462071. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC10462071/ (Full text)

Transfer of IgG from Long COVID patients induces symptomology in mice

Abstract:

SARS-CoV-2 infections worldwide led to a surge in cases of Long COVID, a post-infectious syndrome. It has been hypothesized that autoantibodies play a crucial role in the development of Long COVID and other syndromes, such as fibromyalgia and myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS). In this study, we tested this hypothesis by passively transferring total IgG from Long COVID patients to mice.

Using Glial Fibrillary Acidic Protein (GFAP) and type-I interferon expression, we stratified patients into three Long COVID subgroups, each with unique plasma proteome signatures. Remarkably, IgG transfer from the two subgroups, which are characterized by higher plasma levels of neuronal proteins and leukocyte activation markers, induced pronounced and persistent sensory hypersensitivity with distinct kinetics. Conversely, IgG transfer from the third subgroup, which are characterized by enriched skeletal and cardiac muscle proteome profiles, reduced locomotor activity in mice without affecting their motor coordination.

These findings demonstrate that transfer of IgG from Long COVID patients to mice replicates disease symptoms, underscoring IgG’s causative role in Long COVID pathogenesis. This work proposes a murine model that mirrors Long COVID’s pathophysiological mechanisms, which may be used as a tool for screening and developing targeted therapeutics.

Source: Hung-Jen Chen, Brent Appelman, Hanneke Willemen, Amelie Bos, Judith Prado, Chiara. E. Geyer, Patrícia Silva Santos Ribeiro, Sabine Versteeg, Mads Larsen, Eline Schüchner, Marije K. Bomers, Ayesha H.A. Lavell, Amsterdam UMC COVID-19 biobank, Braeden Charlton, Rob Wüst, W. Joost Wiersinga, Michèle van Vugt, Gestur Vidarsson, Niels Eijkelkamp, Jeroen den Dunnen. Transfer of IgG from Long COVID patients induces symptomology in mice. bioRxiv 2024.05.30.596590; doi: https://doi.org/10.1101/2024.05.30.596590 https://www.biorxiv.org/content/10.1101/2024.05.30.596590v1.full (Full text)

A causal link between autoantibodies and neurological symptoms in long COVID

Summary:

Acute SARS-CoV-2 infection triggers the generation of diverse and functional autoantibodies (AABs), even after mild cases. Persistently elevated autoantibodies have been found in some individuals with long COVID (LC). Using a >21,000 human protein array, we identified diverse AAB targets in LC patients that correlated with their symptoms.

Elevated AABs to proteins in the nervous system were found in LC patients with neurocognitive and neurological symptoms. Purified Immunoglobulin G (IgG) samples from these individuals reacted with human pons tissue and were cross-reactive with mouse sciatic nerves, spinal cord, and meninges. Antibody reactivity to sciatic nerves and meninges correlated with patient-reported headache and disorientation. Passive transfer of IgG from patients to mice led to increased sensitivity and pain, mirroring patient-reported symptoms. Similarly, mice injected with IgG showed loss of balance and coordination, reflecting donor-reported dizziness. Our findings suggest that targeting AABs could benefit some LC patients.

Source: Keyla Santos Guedes de Sa, Julio Silva, Rafael Bayarri-Olmos, Ryan Brinda, Robert Alec Rath Constable, Patricia A. Colom Diaz, Dong il Kwon, Gisele Rodrigues, Li Wenxue, Christopher Baker, Bornali Bhattacharjee, Jamie Wood, Laura Tabacof, Yansheng Liu, David Putrino, Tamas L. Horvath, Akiko Iwasaki. A causal link between autoantibodies and neurological symptoms in long COVID. medRxiv 2024.06.18.24309100; doi: https://doi.org/10.1101/2024.06.18.24309100 https://www.medrxiv.org/content/10.1101/2024.06.18.24309100v1.full-text (Full text)

Central 5-HTergic hyperactivity induces myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS)-like pathophysiology

Abstract:

Objectives: Myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS) is a significant medical challenge, with no indisputable pathophysiological mechanism identified to date.

Methods: Based on clinical clues, we hypothesized that 5-hydroxytryptamine (5-HT) hyperactivation is implicated in the pathogenic causes of ME/CFS and the associated symptoms. We experimentally evaluated this hypothesis in a series of mouse models.

Results: High-dose selective serotonin reuptake inhibitor (SSRI) treatment induced intra- and extracellular serotonin spillover in the dorsal raphe nuclei of mice. This condition resulted in severe fatigue (rota-rod, fatigue rotating wheel and home-cage activity tests) and ME/CFS-associated symptoms (nest building, plantar and open field test), along with dysfunction in the hypothalamic-pituitary-adrenal (HPA) axis response to exercise challenge. These ME/CFS-like features induced by excess serotonin were additionally verified using both a 5-HT synthesis inhibitor and viral vector for Htr1a (5-HT1A receptor) gene knockdown.

Conclusions: Our findings support the involvement of 5-HTergic hyperactivity in the pathophysiology of ME/CFS. This ME/CFS-mimicking animal model would be useful for understanding ME/CFS biology and its therapeutic approaches.

Source: Lee JS, Kang JY, Park SY, Hwang SJ, Bae SJ, Son CG. Central 5-HTergic hyperactivity induces myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS)-like pathophysiology. J Transl Med. 2024 Jan 8;22(1):34. doi: 10.1186/s12967-023-04808-x. PMID: 38191373. https://translational-medicine.biomedcentral.com/articles/10.1186/s12967-023-04808-x (Full text)

Dermatologic Changes in Experimental Model of Long-COVID

Abstract:

The COVID-19 pandemic, declared in early 2020, is an unprecedented global health crisis, causing over 7.0 million deaths and ongoing challenges. While the pharmaceutical industry expedited vaccine development, mutant SARS-CoV-2 strains remain a major fear. Moreover, concerns regarding the long-term health repercussions of COVID-19-affected individuals persist since individuals affected by mild and moderate to severe SARS-CoV-2 infection experience long-term cardiovascular complications, liver dysfunction, pulmonary afflictions, kidney impairments, and most importantly neurocognitive deficits.
In recent studies, we documented pathophysiological changes in various organs following the post-acute infection of mice with murine hepatitis virus-1 (MHV-1), a coronavirus, at both 7 days and 12 months after infection. One part of the body that can be drastically affected by SARS-CoV-2 is the skin. Studies have shown major changes in the skin post-acute SARS CoV-2 infection in humans. However, long-term dermatologic changes post-COVID have never been explored.
For the first time, we show several cutaneous findings both at the acute stages and long-term post-infection of mice with MHV-1 coronavirus (a promising experimental model to study acute and long-COVID). Precisely, we found destruction of the epidermal layer, an increase in the number of hair follicles, extensive collagen deposition in the dermal layer, and hyperplasticity of the sebaceous glands at the acute stages, along with thinning of the panniculus carnosus, as well as the adventitial layer, which corresponds well with studies in humans.
In contrast, the cutaneous investigation in the long-COVID phase shows the absence of hair follicles from both the epidermal and dermal layers, the destruction of adipose tissues, and the devastation of the epidermal layer. Further, treatment of these mice with a 15 amino acid synthetic peptide, SPIKENET (SPK), which was effective in preventing Spike glycoprotein-1 binding with host receptors, as well as has a potent anti-inflammatory response to severe inflammatory stimulus) restored the loss of hair follicles and re-architected the epidermal and dermal layers.
Additionally, destruction in fatty tissue in the infected mice was successfully restored post-treatment with SPK. These findings suggest that SARS-CoV-2 initiates the changes early post-infection, leading to devastating skin alterations in the long term which can be prevented by our newly identified peptide drug SPK.
Source: Hussain, H.; Paidas, M.J.; Rajalakshmi, R.; Fadel, A.; Ali, M.; Chen, P.; Jayakumar, A.R. Dermatologic Changes in Experimental Model of Long-COVID. Preprints 2023, 2023122339. https://doi.org/10.20944/preprints202312.2339.v1 https://www.preprints.org/manuscript/202312.2339/v1 (Full text available as PDF file)

Comparative single-cell analysis reveals IFN-γ as a driver of respiratory sequelae post COVID-19

Abstract:

Post-acute sequelae of SARS-CoV-2 infection (PASC) represents an urgent public health challenge, with its impact resonating in over 60 million individuals globally. While a growing body of evidence suggests that dysregulated immune reactions may be linked with PASC symptoms, most investigations have primarily centered around blood studies, with few focusing on samples derived from post-COVID affected tissues. Further, clinical studies alone often provide correlative insights rather than causal relationships. Thus, it is essential to compare clinical samples with relevant animal models and conduct functional experiments to truly understand the etiology of PASC.

In this study, we have made comprehensive comparisons between bronchoalveolar lavage fluid (BAL) single-cell RNA sequencing (scRNAseq) data derived from clinical PASC samples and relevant PASC mouse models. This revealed a strong pro-fibrotic monocyte-derived macrophage response in respiratory PASC (R-PASC) in both humans and mice, and abnormal interactions between pulmonary macrophages and respiratory resident T cells.

IFN-g emerged as a key node mediating the immune anomalies in R-PASC. Strikingly, neutralizing IFN-g post the resolution of acute infection reduced lung inflammation, tissue fibrosis, and improved pulmonary gas-exchange function in two mouse models of R-PASC. Our study underscores the importance of performing comparative analysis to understand the root cause of PASC for developing effective therapies.

Source: Jie Sun, Chaofan Li, Wei Qian, Xiaoqin Wei. Comparative single-cell analysis reveals IFN-γ as a driver of respiratory sequelae post COVID-19. bioRxiv 2023.10.03.560739; doi: https://doi.org/10.1101/2023.10.03.560739 https://www.biorxiv.org/content/10.1101/2023.10.03.560739v1

Core mitochondrial genes are down-regulated during SARS-CoV-2 infection of rodent and human hosts

Editor’s summary:

SARS-CoV-2 needs host cells to generate molecules for viral replication and propagation. Guarnieri et al. now show that the virus is able to block expression of both nuclear-encoded and mitochondrial-encoded mitochondrial genes, resulting in impaired host mitochondrial function. They analyzed human nasopharyngeal samples and autopsy tissues from patients with COVID-19 and tissues from hamsters and mice infected with SARS-CoV-2. Host cells attempt to compensate by activating innate immune defenses and mitochondrial gene expression, but chronically impaired mitochondrial function ultimately may result in serious COVID-19 sequelae such as organ failure. —Orla Smith
Abstract:
Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) viral proteins bind to host mitochondrial proteins, likely inhibiting oxidative phosphorylation (OXPHOS) and stimulating glycolysis. We analyzed mitochondrial gene expression in nasopharyngeal and autopsy tissues from patients with coronavirus disease 2019 (COVID-19).
In nasopharyngeal samples with declining viral titers, the virus blocked the transcription of a subset of nuclear DNA (nDNA)–encoded mitochondrial OXPHOS genes, induced the expression of microRNA 2392, activated HIF-1α to induce glycolysis, and activated host immune defenses including the integrated stress response.
In autopsy tissues from patients with COVID-19, SARS-CoV-2 was no longer present, and mitochondrial gene transcription had recovered in the lungs. However, nDNA mitochondrial gene expression remained suppressed in autopsy tissue from the heart and, to a lesser extent, kidney, and liver, whereas mitochondrial DNA transcription was induced and host-immune defense pathways were activated.
During early SARS-CoV-2 infection of hamsters with peak lung viral load, mitochondrial gene expression in the lung was minimally perturbed but was down-regulated in the cerebellum and up-regulated in the striatum even though no SARS-CoV-2 was detected in the brain. During the mid-phase SARS-CoV-2 infection of mice, mitochondrial gene expression was starting to recover in mouse lungs.
These data suggest that when the viral titer first peaks, there is a systemic host response followed by viral suppression of mitochondrial gene transcription and induction of glycolysis leading to the deployment of antiviral immune defenses. Even when the virus was cleared and lung mitochondrial function had recovered, mitochondrial function in the heart, kidney, liver, and lymph nodes remained impaired, potentially leading to severe COVID-19 pathology.
Source: Guarnieri JW, Dybas JM, Fazelinia H, Kim MS, Frere J, Zhang Y, Soto Albrecht Y, Murdock DG, Angelin A, Singh LN, Weiss SL, Best SM, Lott MT, Zhang S, Cope H, Zaksas V, Saravia-Butler A, Meydan C, Foox J, Mozsary C, Bram Y, Kidane Y, Priebe W, Emmett MR, Meller R, Demharter S, Stentoft-Hansen V, Salvatore M, Galeano D, Enguita FJ, Grabham P, Trovao NS, Singh U, Haltom J, Heise MT, Moorman NJ, Baxter VK, Madden EA, Taft-Benz SA, Anderson EJ, Sanders WA, Dickmander RJ, Baylin SB, Wurtele ES, Moraes-Vieira PM, Taylor D, Mason CE, Schisler JC, Schwartz RE, Beheshti A, Wallace DC. Core mitochondrial genes are down-regulated during SARS-CoV-2 infection of rodent and human hosts. Sci Transl Med. 2023 Aug 9;15(708):eabq1533. doi: 10.1126/scitranslmed.abq1533. Epub 2023 Aug 9. PMID: 37556555. https://pubmed.ncbi.nlm.nih.gov/37556555/

Circulating Reelin promotes inflammation and modulates disease activity in acute and long COVID-19 cases

Abstract:

Thromboembolic complications and excessive inflammation are frequent in severe COVID-19, potentially leading to long COVID. In non-COVID studies, we and others demonstrated that circulating Reelin promotes leukocyte infiltration and thrombosis. Thus, we hypothesized that Reelin participates in endothelial dysfunction and hyperinflammation during COVID-19.

We showed that Reelin was increased in COVID-19 patients and correlated with the disease activity. In the severe COVID-19 group, we observed a hyperinflammatory state, as judged by increased concentration of cytokines (IL-1α, IL-4, IL-6, IL-10 and IL-17A), chemokines (IP-10 and MIP-1β), and adhesion markers (E-selectin and ICAM-1).

Reelin level was correlated with IL-1α, IL-4, IP-10, MIP-1β, and ICAM-1, suggesting a specific role for Reelin in COVID-19 progression. Furthermore, Reelin and all of the inflammatory markers aforementioned returned to normal in a long COVID cohort, showing that the hyperinflammatory state was resolved. Finally, we tested Reelin inhibition with the anti-Reelin antibody CR-50 in hACE2 transgenic mice infected with SARS-CoV-2. CR-50 prophylactic treatment decreased mortality and disease severity in this model.

These results demonstrate a direct proinflammatory function for Reelin in COVID-19 and identify it as a drug target. This work opens translational clinical applications in severe SARS-CoV-2 infection and beyond in auto-inflammatory diseases.

Source: Calvier L, Drelich A, Hsu J, Tseng CT, Mina Y, Nath A, Kounnas MZ, Herz J. Circulating Reelin promotes inflammation and modulates disease activity in acute and long COVID-19 cases. Front Immunol. 2023 Jun 27;14:1185748. doi: 10.3389/fimmu.2023.1185748. PMID: 37441066; PMCID: PMC10333573. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC10333573/ (Full text)

Serum from Myalgic encephalomyelitis/chronic fatigue syndrome patients causes loss of coherence in cellular circadian rhythms

Abstract:

Myalgic Encephalomyelitis/Chronic Fatigue Syndrome (ME/CFS) is a disabling disorder characterized by disrupted daily patterns of activity, sleep, and physiology. Past studies in ME/CFS patients have examined circadian rhythms, suggested that desynchronization between central and peripheral rhythms may be an important pathological feature, and identified associated changes in post-inflammatory cytokines such as transforming growth factor beta (TGFB). However, no previous studies have examined circadian rhythms in ME/CFS using cellular models or studied the role of cytokines on circadian rhythms.

In this study, we used serum samples previously collected from ME/CFS patients (n = 20) selected for the presence of insomnia symptoms and matched controls (n = 20) to determine the effects of serum factors and TGFB on circadian rhythms in NIH3T3 mouse immortalized fibroblasts stably transfected with the Per2-luc bioluminescent circadian reporter.

Compared to control serum, ME/CFS serum caused a significant loss of rhythm robustness (decreased goodness of fit) and nominally increased the rate of damping of cellular rhythms. Damping rate was associated with insomnia severity in ME/CFS patients using the Pittsburgh Sleep Quality Index (PSQI). Recombinant TGFB1 peptide applied to cells reduced rhythm amplitude, caused phase delay and decreased robustness of rhythms.

However, there was no difference in TGFB1 levels between ME/CFS and control serum indicating the effects of serum on cellular rhythms cannot be explained by levels of this cytokine. Future studies will be required to identify additional serum factors in ME/CFS patients that alter circadian rhythms in cells.

Source: Heather Wei, Zoe Adelsheim, Rita Fischer, Michael J. McCarthy. Serum from Myalgic encephalomyelitis/chronic fatigue syndrome patients causes loss of coherence in cellular circadian rhythms. Journal of Neuroimmunology. Available online 24 June 2023, 578142. https://doi.org/10.1016/j.jneuroim.2023.578142 https://www.sciencedirect.com/science/article/abs/pii/S0165572823001285

Recuperative herbal formula Jing Si maintains vasculature permeability balance, regulates inflammation and assuages concomitants of “Long-Covid”

Abstract:

Coronavirus disease 2019 (COVID-19) is a worldwide health threat that has long-term effects on the patients and there is currently no efficient cure prescribed for the treatment and the prolonging effects. Traditional Chinese medicines (TCMs) have been reported to exert therapeutic effect against COVID-19.

In this study, the therapeutic effects of Jing Si herbal tea (JSHT) against COVID-19 infection and associated long-term effects were evaluated in different in vitro and in vivo models. The anti-inflammatory effects of JSHT were studied in lipopolysaccharide (LPS)-stimulated RAW 264.7 cells and in Omicron pseudotyped virus-induced acute lung injury model. The effect of JSHT on cellular stress was determined in HK-2 proximal tubular cells and H9c2 cardiomyoblasts.

The therapeutic benefits of JSHT on anhedonia and depression symptoms associated with long COVID were evaluated in mice models for unpredictable chronic mild stress (UCMS). JSHT inhibited the NF-ƙB activities, and significantly reduced LPS-induced expression of TNFα, COX-2, NLRP3 inflammasome, and HMGB1. JSHT was also found to significantly suppress the production of NO by reducing iNOS expression in LPS-stimulated RAW 264.7 cells.

Further, the protective effects of JSHT on lung tissue were confirmed based on mitigation of lung injury, repression in TMRRSS2 and HMGB-1 expression and reduction of cytokine storm in the Omicron pseudotyped virus-induced acute lung injury model. JSHT treatment in UCMS models also relieved chronic stress and combated depression symptoms. The results therefore show that JSHT attenuates the cytokine storm by repressing NF-κB cascades and provides the protective functions against symptoms associated with long COVID-19 infection.

Source: Chiang CY, Lin YJ, Weng WT, Lin HD, Lu CY, Chen WJ, Shih CY, Lin PY, Lin SZ, Ho TJ, Shibu MA, Huang CY. Recuperative herbal formula Jing Si maintains vasculature permeability balance, regulates inflammation and assuages concomitants of “Long-Covid”. Biomed Pharmacother. 2023 Apr 26;163:114752. doi: 10.1016/j.biopha.2023.114752. Epub ahead of print. PMID: 37116351; PMCID: PMC10130602. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC10130602/ (Full text)