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Ullah MN, Rowan NR, Lane AP. Neuroimmune interactions in the olfactory epithelium: maintaining a sensory organ at an immune barrier interface. Trends Immunol 2024; 45:987-1000. [PMID: 39550314 PMCID: PMC11624989 DOI: 10.1016/j.it.2024.10.005] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2024] [Revised: 10/18/2024] [Accepted: 10/20/2024] [Indexed: 11/18/2024]
Abstract
While primarily a sensory organ, the mammalian olfactory epithelium (OE) also plays a critical role as an immune barrier. Mechanisms governing interactions between the immune system and this specialized chemosensory tissue are gaining interest, in part sparked by the COVID-19 pandemic. Regulated inflammation is intrinsic to normal mucosal healing and homeostasis, but prolonged OE inflammation is associated with persistent loss of smell, belying the intertwining of local mucosal immunology and olfactory function. Evidence supports bidirectional communication between OE cells and the immune system in health and disease. Recent investigations suggest that neuro-immune cross-talk modulates olfactory stem cell behavior and neuronal regeneration dynamics, prioritizing the epithelial-like non-neuronal framework with immune barrier function at the expense of the neurosensory organ in chronic inflammation.
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Affiliation(s)
- Mohammed N Ullah
- Department of Otolaryngology - Head and Neck Surgery, Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Nicholas R Rowan
- Department of Otolaryngology - Head and Neck Surgery, Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Andrew P Lane
- Department of Otolaryngology - Head and Neck Surgery, Johns Hopkins University School of Medicine, Baltimore, MD, USA.
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2
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Lupi L, Vitiello A, Parolin C, Calistri A, Garzino-Demo A. The Potential Role of Viral Persistence in the Post-Acute Sequelae of SARS-CoV-2 Infection (PASC). Pathogens 2024; 13:388. [PMID: 38787240 PMCID: PMC11123686 DOI: 10.3390/pathogens13050388] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2024] [Revised: 04/26/2024] [Accepted: 05/06/2024] [Indexed: 05/25/2024] Open
Abstract
The infection by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is associated not only with the development of acute disease but also with long-term symptoms or post-acute sequelae of SARS-CoV-2 (PASC). Multiple lines of evidence support that some viral antigens and RNA can persist for up to 15 months in multiple organs in the body, often after apparent clearance from the upper respiratory system, possibly leading to the persistence of symptoms. Activation of the immune system to viral antigens is observed for a prolonged time, providing indirect evidence of the persistence of viral elements after acute infection. In the gastrointestinal tract, the persistence of some antigens could stimulate the immune system, shaping the local microbiota with potential systemic effects. All of these interactions need to be investigated, taking into account predisposing factors, multiplicity of pathogenic mechanisms, and stratifying populations of vulnerable individuals, particularly women, children, and immunocompromised individuals, where SARS-CoV-2 may present additional challenges.
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Affiliation(s)
- Lorenzo Lupi
- Department of Molecular Medicine, University of Padova, 35121 Padova, Italy; (L.L.); (A.V.); (C.P.); (A.C.)
| | - Adriana Vitiello
- Department of Molecular Medicine, University of Padova, 35121 Padova, Italy; (L.L.); (A.V.); (C.P.); (A.C.)
| | - Cristina Parolin
- Department of Molecular Medicine, University of Padova, 35121 Padova, Italy; (L.L.); (A.V.); (C.P.); (A.C.)
| | - Arianna Calistri
- Department of Molecular Medicine, University of Padova, 35121 Padova, Italy; (L.L.); (A.V.); (C.P.); (A.C.)
| | - Alfredo Garzino-Demo
- Department of Molecular Medicine, University of Padova, 35121 Padova, Italy; (L.L.); (A.V.); (C.P.); (A.C.)
- Department of Microbial Pathogenesis, School of Dentistry, University of Maryland, Baltimore, MD 21201, USA
- Department of Microbiology and Immunology, School of Medicine, University of Maryland, Baltimore, MD 21201, USA
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Gheorghita R, Soldanescu I, Lobiuc A, Caliman Sturdza OA, Filip R, Constantinescu – Bercu A, Dimian M, Mangul S, Covasa M. The knowns and unknowns of long COVID-19: from mechanisms to therapeutical approaches. Front Immunol 2024; 15:1344086. [PMID: 38500880 PMCID: PMC10944866 DOI: 10.3389/fimmu.2024.1344086] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2023] [Accepted: 02/14/2024] [Indexed: 03/20/2024] Open
Abstract
The coronavirus disease 2019 (COVID-19) pandemic caused by SARS-CoV-2 has been defined as the greatest global health and socioeconomic crisis of modern times. While most people recover after being infected with the virus, a significant proportion of them continue to experience health issues weeks, months and even years after acute infection with SARS-CoV-2. This persistence of clinical symptoms in infected individuals for at least three months after the onset of the disease or the emergence of new symptoms lasting more than two months, without any other explanation and alternative diagnosis have been named long COVID, long-haul COVID, post-COVID-19 conditions, chronic COVID, or post-acute sequelae of SARS-CoV-2 (PASC). Long COVID has been characterized as a constellation of symptoms and disorders that vary widely in their manifestations. Further, the mechanisms underlying long COVID are not fully understood, which hamper efficient treatment options. This review describes predictors and the most common symptoms related to long COVID's effects on the central and peripheral nervous system and other organs and tissues. Furthermore, the transcriptional markers, molecular signaling pathways and risk factors for long COVID, such as sex, age, pre-existing condition, hospitalization during acute phase of COVID-19, vaccination, and lifestyle are presented. Finally, recommendations for patient rehabilitation and disease management, as well as alternative therapeutical approaches to long COVID sequelae are discussed. Understanding the complexity of this disease, its symptoms across multiple organ systems and overlapping pathologies and its possible mechanisms are paramount in developing diagnostic tools and treatments.
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Affiliation(s)
- Roxana Gheorghita
- Victor Babes University of Medicine and Pharmacy, Timisoara, Romania
- Department of Biomedical Sciences, College of Medicine and Biological Science, University of Suceava, Suceava, Romania
| | - Iuliana Soldanescu
- Integrated Center for Research, Development and Innovation for Advanced Materials, Nanotechnologies, Manufacturing and Control Distributed Systems (MANSiD), University of Suceava, Suceava, Romania
| | - Andrei Lobiuc
- Department of Biomedical Sciences, College of Medicine and Biological Science, University of Suceava, Suceava, Romania
| | - Olga Adriana Caliman Sturdza
- Department of Biomedical Sciences, College of Medicine and Biological Science, University of Suceava, Suceava, Romania
- Suceava Emergency Clinical County Hospital, Suceava, Romania
| | - Roxana Filip
- Department of Biomedical Sciences, College of Medicine and Biological Science, University of Suceava, Suceava, Romania
- Suceava Emergency Clinical County Hospital, Suceava, Romania
| | - Adela Constantinescu – Bercu
- Department of Biomedical Sciences, College of Medicine and Biological Science, University of Suceava, Suceava, Romania
- Institute of Cardiovascular Science, Hemostasis Research Unit, University College London (UCL), London, United Kingdom
| | - Mihai Dimian
- Integrated Center for Research, Development and Innovation for Advanced Materials, Nanotechnologies, Manufacturing and Control Distributed Systems (MANSiD), University of Suceava, Suceava, Romania
- Department of Computer, Electronics and Automation, University of Suceava, Suceava, Romania
| | - Serghei Mangul
- Department of Clinical Pharmacy, USC Alfred E. Mann School of Pharmacy and Pharmaceutical Sciences, University of Southern California, Los Angeles, CA, United States
- Department of Quantitative and Computational Biology, USC Dornsife College of Letters, Arts and Sciences, University of Southern California (USC), Los Angeles, CA, United States
| | - Mihai Covasa
- Department of Biomedical Sciences, College of Medicine and Biological Science, University of Suceava, Suceava, Romania
- Department of Basic Medical Sciences, Western University of Health Sciences, College of Osteopathic Medicine, Pomona, CA, United States
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Wellford SA, Moseman EA. Olfactory immune response to SARS-CoV-2. Cell Mol Immunol 2024; 21:134-143. [PMID: 38143247 PMCID: PMC10806031 DOI: 10.1038/s41423-023-01119-5] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2023] [Accepted: 12/04/2023] [Indexed: 12/26/2023] Open
Abstract
Numerous pathogens can infect the olfactory tract, yet the pandemic caused by SARS-CoV-2 has strongly emphasized the importance of the olfactory mucosa as an immune barrier. Situated in the nasal passages, the olfactory mucosa is directly exposed to the environment to sense airborne odorants; however, this also means it can serve as a direct route of entry from the outside world into the brain. As a result, olfactotropic infections can have serious consequences, including dysfunction of the olfactory system, CNS invasion, dissemination to the lower respiratory tract, and transmission between individuals. Recent research has shown that a distinctive immune response is needed to protect this neuronal and mucosal tissue. A better understanding of innate, adaptive, and structural immune barriers in the olfactory mucosa is needed to develop effective therapeutics and vaccines against olfactotropic microbes such as SARS-CoV-2. Here, we summarize the ramifications of SARS-CoV-2 infection of the olfactory mucosa, review the subsequent immune response, and discuss important areas of future research for olfactory immunity to infectious disease.
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Affiliation(s)
- Sebastian A Wellford
- Department of Integrative Immunobiology, Duke University School of Medicine, Durham, NC, USA
| | - E Ashley Moseman
- Department of Integrative Immunobiology, Duke University School of Medicine, Durham, NC, USA.
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