Microbiota and Its Impact on the Immune System in COVID-19—A Narrative Review

The microbiota is of interest for the development of a therapeutic strategy against SARS-CoV-2 coronavirus disease 2019 (COVID-19) due to its impact on the host immune system. Proven communications of the gut microbiota with the pulmonary microbiota (gut–lung axis) and the pathway of neural connections between the gut and brain (gut–brain axis) may be important in the face of the pandemic. SARS-CoV-2 was shown to affect almost all organs because of the presence of a host receptor known as angiotensin converting enzyme 2 (ACE2). The ACE2 receptor is mainly present in the brush border of intestinal enterocytes, ciliary cells, and type II alveolar epithelial cells in the lungs. The transport function of ACE2 has been linked to the ecology of gut microbes in the digestive tract, suggesting that COVID-19 may be related to the gut microbiota. The severity of COVID-19 may be associated with a number of comorbidities, such as hypertension, diabetes, obesity, and/or old age; therefore, attention is also paid to multiple morbidities and the modulation of microbiota through comorbidities and medications. This paper reviews the research in the context of the state of the intestinal microbiota and its impact on the cells of the immune system during the SARS-CoV-2 pandemic.

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Microbiota-Immune System Interactions in Human Neurological Disorders

CNS & Neurological Disorders - Drug Targets ◽

10.2174/1871527319666200726222138 ◽

2020 ◽

Vol 19 (7) ◽

pp. 509-526

Author(s):

Qin Huang ◽

Fang Yu ◽

Di Liao ◽

Jian Xia

Keyword(s):

Immune System ◽

Gut Microbiota ◽

Neurological Disorders ◽

Brain Function ◽

Neurological Diseases ◽

Host Immune System ◽

Gut Dysbiosis ◽

Characteristic Features ◽

Novel Therapeutic Strategies

: Recent studies implicate microbiota-brain communication as an essential factor for physiology and pathophysiology in brain function and neurodevelopment. One of the pivotal mechanisms about gut to brain communication is through the regulation and interaction of gut microbiota on the host immune system. In this review, we will discuss the role of microbiota-immune systeminteractions in human neurological disorders. The characteristic features in the development of neurological diseases include gut dysbiosis, the disturbed intestinal/Blood-Brain Barrier (BBB) permeability, the activated inflammatory response, and the changed microbial metabolites. Neurological disorders contribute to gut dysbiosis and some relevant metabolites in a top-down way. In turn, the activated immune system induced by the change of gut microbiota may deteriorate the development of neurological diseases through the disturbed gut/BBB barrier in a down-top way. Understanding the characterization and identification of microbiome-immune- brain signaling pathways will help us to yield novel therapeutic strategies by targeting the gut microbiome in neurological disease.

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The Microbiotic Highway to Health—New Perspective on Food Structure, Gut Microbiota, and Host Inflammation

Nutrients ◽

10.3390/nu10111590 ◽

2018 ◽

Vol 10 (11) ◽

pp. 1590 ◽

Cited By ~ 13

Author(s):

Nina Hansen ◽

Anette Sams

Keyword(s):

Immune System ◽

Gut Microbiota ◽

Dietary Habits ◽

Gut Hormones ◽

Host Immune System ◽

Inflammatory Conditions ◽

Food Structure ◽

New Perspective ◽

And Function ◽

The Impact

This review provides evidence that not only the content of nutrients but indeed the structural organization of nutrients is a major determinant of human health. The gut microbiota provides nutrients for the host by digesting food structures otherwise indigestible by human enzymes, thereby simultaneously harvesting energy and delivering nutrients and metabolites for the nutritional and biological benefit of the host. Microbiota-derived nutrients, metabolites, and antigens promote the development and function of the host immune system both directly by activating cells of the adaptive and innate immune system and indirectly by sustaining release of monosaccharides, stimulating intestinal receptors and secreting gut hormones. Multiple indirect microbiota-dependent biological responses contribute to glucose homeostasis, which prevents hyperglycemia-induced inflammatory conditions. The composition and function of the gut microbiota vary between individuals and whereas dietary habits influence the gut microbiota, the gut microbiota influences both the nutritional and biological homeostasis of the host. A healthy gut microbiota requires the presence of beneficial microbiotic species as well as vital food structures to ensure appropriate feeding of the microbiota. This review focuses on the impact of plant-based food structures, the “fiber-encapsulated nutrient formulation”, and on the direct and indirect mechanisms by which the gut microbiota participate in host immune function.

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The Bacterium Frischella perrara Causes Scab Formation in the Gut of its Honeybee Host

mBio ◽

10.1128/mbio.00193-15 ◽

2015 ◽

Vol 6 (3) ◽

Cited By ~ 49

Author(s):

Philipp Engel ◽

Kelsey D. Bartlett ◽

Nancy A. Moran

Keyword(s):

Immune Response ◽

Immune System ◽

Gut Microbiota ◽

Bacterial Colonization ◽

Bacterial Species ◽

Host Immune System ◽

Natural Ecosystems ◽

Epithelial Surface ◽

Host Interactions ◽

Key Species

ABSTRACT Honeybees harbor well-defined bacterial communities in their guts. The major members of these communities appear to benefit the host, but little is known about how they interact with the host and specifically how they interface with the host immune system. In the pylorus, a short region between the midgut and hindgut, honeybees frequently exhibit scab-like structures on the epithelial gut surface. These structures are reminiscent of a melanization response of the insect immune system. Despite the wide distribution of this phenotype in honeybee populations, its cause has remained elusive. Here, we show that the presence of a common member of the bee gut microbiota, the gammaproteobacterium Frischella perrara, correlates with the appearance of the scab phenotype. Bacterial colonization precedes scab formation, and F. perrara specifically localizes to the melanized regions of the host epithelium. Under controlled laboratory conditions, we demonstrate that exposure of microbiota-free bees to F. perrara but not to other bacteria results in scab formation. This shows that F. perrara can become established in a spatially restricted niche in the gut and triggers a morphological change of the epithelial surface, potentially due to a host immune response. As an intermittent colonizer, this bacterium holds promise for addressing questions of community invasion in a simple yet relevant model system. Moreover, our results show that gut symbionts of bees engage in differential host interactions that are likely to affect gut homeostasis. Future studies should focus on how these different gut bacteria impact honeybee health. IMPORTANCE As pollinators, honeybees are key species for agricultural and natural ecosystems. Their guts harbor simple communities composed of characteristic bacterial species. Because of these features, bees are ideal systems for studying fundamental aspects of gut microbiota-host interactions. However, little is known about how these bacteria interact with their host. Here, we show that a common member of the bee gut microbiota causes the formation of a scab-like structure on the gut epithelium of its host. This phenotype was first described in 1946, but since then it has not been much further characterized, despite being found in bee populations worldwide. The scab phenotype is reminiscent of melanization, a conserved innate immune response of insects. Our results show that high abundance of one member of the bee gut microbiota triggers this specific phenotype, suggesting that the gut microbiota composition can affect the immune status of this key pollinator species.

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The Multifaceted Effects of Gut Microbiota on the Immune System of the Intestinal Mucosa

Immuno ◽

10.3390/immuno1040041 ◽

2021 ◽

Vol 1 (4) ◽

pp. 583-594

Author(s):

Takehiro Hirano ◽

Hiroshi Nakase

Keyword(s):

Immune System ◽

Gut Microbiota ◽

Gut Microbiome ◽

Mucosal Barrier ◽

Host Immune System ◽

Immunological Responses ◽

Gut Homeostasis ◽

Inflammatory Processes ◽

And Oxidative Stress

The gut microbiota has diverse microbial components, including bacteria, viruses, and fungi. The interaction between gut microbiome components and immune responses has been studied extensively over the last decade. Several studies have reported the potential role of the gut microbiome in maintaining gut homeostasis and the development of disease. The commensal microbiome can preserve the integrity of the mucosal barrier by acting on the host immune system. Contrastingly, dysbiosis-induced inflammation can lead to the initiation and progression of several diseases through inflammatory processes and oxidative stress. In this review, we describe the multifaceted effects of the gut microbiota on several diseases from the perspective of mucosal immunological responses.

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Use of medicines for covid-19 treatment in patients with loss of kidney function: a narrative review

Brazilian Journal of Nephrology ◽

10.1590/2175-8239-jbn-2020-0105 ◽

2020 ◽

Author(s):

Lucas Lobato Acatauassu Nunes ◽

Tácio de Mendonça Lima

Keyword(s):

Kidney Function ◽

Specific Treatment ◽

Kidney Injury ◽

Alveolar Epithelial Cells ◽

Renal Cells ◽

Angiotensin Converting Enzyme 2 ◽

Factors Associated ◽

Alveolar Epithelial ◽

Heart Blood ◽

Dose Recommendations

ABSTRACT Covid-19 has been identified as the cause of acute respiratory disease with interstitial and alveolar pneumonia, but it can affect several organs, such as kidneys, heart, blood, nervous system and digestive tract. The disease-causing agent (Sars-CoV-2) has a binding structure to the angiotensin-converting enzyme 2 (ACE2) receptor, enabling entry into cells that express ACE2, such as the pulmonary alveolar epithelial cells. However, studies also indicate the possibility of damage to renal cells, since these cells express high levels of ACE2. Currently, there is no evidence to indicate a specific treatment for covid-19. Several drugs have been used, and some of them may have their excretion process altered in patients with abnormal kidney function. To date, there are no studies that assist health professionals in adjusting the dose of these drugs. Thus, this study aims to review and discuss the topic, taking into account factors associated with kidney injury in covid-19, as well as pharmacokinetic aspects and dose recommendations of the main drugs used for covid-19.

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The Role of Gut Microbiota in Tumor Immunotherapy

Journal of Immunology Research ◽

10.1155/2021/5061570 ◽

2021 ◽

Vol 2021 ◽

pp. 1-12

Author(s):

Miao Wu ◽

Jiawei Bai ◽

Chengtai Ma ◽

Jie Wei ◽

Xianjin Du

Keyword(s):

Immune System ◽

Gut Microbiota ◽

Intestinal Microbiota ◽

Adverse Reactions ◽

Tumor Development ◽

Tumor Immunotherapy ◽

Host Immune System ◽

Hematological Tumors ◽

New Research

Tumor immunotherapy is the fourth therapy after surgery, chemotherapy, and radiotherapy. It has made great breakthroughs in the treatment of some epithelial tumors and hematological tumors. However, its adverse reactions are common or even more serious, and the response rate in some solid tumors is not satisfactory. With the maturity of genomics and metabolomics technologies, the effect of intestinal microbiota in tumor development and treatment has gradually been recognized. The microbiota may affect tumor immunity by regulating the host immune system and tumor microenvironment. Some bacteria help fight tumors by activating immunity, while some bacteria mediate immunosuppression to help cancer cells escape from the immune system. More and more studies have revealed that the effects and complications of tumor immunotherapy are related to the composition of the gut microbiota. The composition of the intestinal microbiota that is sensitive to treatment or prone to adverse reactions has certain characteristics. These characteristics may be used as biomarkers to predict the prognosis of immunotherapy and may also be developed as “immune potentiators” to assist immunotherapy. Some clinical and preclinical studies have proved that microbial intervention, including microbial transplantation, can improve the sensitivity of immunotherapy or reduce adverse reactions to a certain extent. With the development of gene editing technology and nanotechnology, the design and development of engineered bacteria that contribute to immunotherapy has become a new research hotspot. Based on the relationship between the intestinal microbiota and immunotherapy, the correct mining of microbial information and the development of reasonable and feasible microbial intervention methods are expected to optimize tumor immunotherapy to a large extent and bring new breakthroughs in tumor treatment.

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ACE2 polymorphisms and individual susceptibility to SARS-CoV-2 infection: insights from an in silico study

10.1101/2020.04.23.057042 ◽

2020 ◽

Cited By ~ 13

Author(s):

Matteo Calcagnile ◽

Patricia Forgez ◽

Antonio Iannelli ◽

Cecilia Bucci ◽

Marco Alifano ◽

...

Keyword(s):

In Silico ◽

Alveolar Epithelial Cells ◽

Nucleotide Polymorphisms ◽

Related Factors ◽

Single Nucleotide ◽

Angiotensin Converting Enzyme 2 ◽

Alveolar Epithelial ◽

African People ◽

In Silico Study ◽

Ace2 Gene

AbstractThe current SARS covid-19 epidemic spread appears to be influenced by ethnical, geographical and sex-related factors that may involve genetic susceptibility to diseases. Similar to SARS-CoV, SARS-CoV-2 exploits angiotensin-converting enzyme 2 (ACE2) as a receptor to invade cells, notably type II alveolar epithelial cells. Importantly, ACE2 gene is highly polymorphic. Here we have used in silico tools to analyze the possible impact of ACE2 single-nucleotide polymorphisms (SNPs) on the interaction with SARS-CoV-2 spike glycoprotein. We found that S19P (common in African people) and K26R (common in European people) were, among the most diffused SNPs worldwide, the only two SNPs that were able to potentially affect the interaction of ACE2 with SARS-CoV-2 spike. FireDock simulations demonstrated that while S19P may decrease, K26R might increase the ACE2 affinity for SARS-CoV-2 Spike. This finding suggests that the S19P may genetically protect, and K26R may predispose to more severe SARS-CoV-2 disease.

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The role of microbiome in rheumatoid arthritis treatment

Therapeutic Advances in Musculoskeletal Disease ◽

10.1177/1759720x19844632 ◽

2019 ◽

Vol 11 ◽

pp. 1759720X1984463 ◽

Cited By ~ 13

Author(s):

Rahul Bodkhe ◽

Baskar Balakrishnan ◽

Veena Taneja

Keyword(s):

Rheumatoid Arthritis ◽

Immune System ◽

Gut Microbiota ◽

Autoimmune Disorder ◽

Host Immune System ◽

Microbial Composition ◽

Drug Induced ◽

Partial Restoration ◽

Genetic And Environmental Factors ◽

The Impact

Rheumatoid arthritis (RA) is an autoimmune disorder with multifactorial etiology; both genetic and environmental factors are known to be involved in pathogenesis. Treatment with disease-modifying antirheumatic drugs (DMARDs) plays an essential role in controlling disease progression and symptoms. DMARDs have immunomodulatory properties and suppress immune response by interfering in various pro-inflammatory pathways. Recent evidence has shown that the gut microbiota directly and indirectly modulates the host immune system. RA has been associated with dysbiosis of the gut microbiota. Patients with RA treated with DMARDs show partial restoration of eubiotic gut microbiome. Hence, it is essential to understand the impact of DMARDs on the microbial composition and its consequent influences on the host immune system to identify novel therapies for RA. In this review, we discuss the importance of antirheumatic-drug-induced host microbiota modulations and possible probiotics that can generate eubiosis.

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